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Geotechnical Report G3127
RUAKURA DEVELOPMENT Stage 1: Geotechnical Investigation Tainui Group Holdings Limited
Geotechnical Interpretive Report
Ruakura Development: Stage 1 Geotechnical Investigation. Interpretive Report. i
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Contents
1 Introduction ........................................................................................................1
1.1 Our Brief ................................................................................................................................. 1
2 Development Proposals / Activities .................................................................... 2
2.1 Residential Zone(s) ............................................................................................................... 2
2.2 Business Zones (Employment / Industrial) ........................................................................ 3
2.3 Ruakura Logistics (Inland Port) Zone ................................................................................. 3
2.4 Knowledge (Innovation Park / Commercial) Zone ............................................................. 3
2.5 Existing Rural Residential Zone ........................................................................................... 4
3 Site Description – Stage 1 investigation area ...................................................... 4
3.1 General Topography and Description .................................................................................. 4
3.2 Proposed Residential Zones in North West of Site ............................................................. 4
3.3 Proposed Business Zone North of AGresearch ................................................................... 5
3.4 Proposed Inland Port Zone ................................................................................................... 6
3.5 Business Zone South of Inland Port..................................................................................... 6
4 Desk Study ......................................................................................................... 7
4.1 Published Geological Information ....................................................................................... 7
4.1 Near Surface Soils Information ............................................................................................ 7
4.2 River Flood Hazard Map ....................................................................................................... 7
4.3 Faulting .................................................................................................................................. 8
4.4 Previous Ground Investigations ........................................................................................... 8
5 Stage 1 Site Investigation ................................................................................... 11
5.1 Exploratory Holes ................................................................................................................ 11
5.2 Insitu Field Tests .................................................................................................................. 11
5.3 Laboratory Testing ............................................................................................................... 12
6 Soil Conditions Encountered ............................................................................. 13
6.1 Fill Material .......................................................................................................................... 13
6.2 Topsoil ................................................................................................................................... 13
6.3 Strata of the Hinuera Formation ......................................................................................... 13
6.4 Bedrock .................................................................................................................................14
6.5 Comparison with Previous Ground Investigations ............................................................14
7 Groundwater .....................................................................................................16
7.1 Shallow Piezometers ............................................................................................................16
7.2 Deep Piezometers ................................................................................................................. 17
7.3 Soakage / Permeability Testing ........................................................................................... 17
8 Laboratory Test Results ....................................................................................19
8.1 Oedometer Consolidation Tests / Organic Contents .........................................................19
8.2 Classification Testing on Fine Grained Soils ......................................................................19
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8.3 NZ Standard Compaction Tests ......................................................................................... 20
8.4 Particle Size Distribution Tests .......................................................................................... 20
8.5 Re-Moulded CBR Tests ....................................................................................................... 20
9 Brief and Development Proposals .................................................................... 22
9.1 Brief ...................................................................................................................................... 22
9.2 Development Proposals ...................................................................................................... 22
10 Interpretation – Calculation Methodology ....................................................... 25
10.1 Potential Fill Material & Induced Settlements .................................................................. 25
10.2 Foundation Bearing Capacity ............................................................................................. 27
10.3 Foundation Settlement ....................................................................................................... 28
10.4 Seismic Characteristics ....................................................................................................... 28
10.5 Liquefaction ......................................................................................................................... 30
10.6 Stormwater Disposal ............................................................................................................ 31
11 Preliminary Geotechnical Considerations ........................................................ 33
11.1 Geotechnical Properties of Soils Encountered .................................................................. 33
11.2 Residential zone – Preliminary Assessment ..................................................................... 34
11.3 Business Zone North of AGresearch .................................................................................. 38
11.4 Inland Port Zone ................................................................................................................. 42
11.5 Business Zone South of Inland Port................................................................................... 47
12 Recommendations ........................................................................................... 50
12.1 Stage 1 Investigation Areas ................................................................................................. 50
12.2 Balance of Ruakura Development ...................................................................................... 50
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Figures
Figure 1: Site Location Plan
Figure 2: Exploratory Hole Location Plan-Residential Zones
Figure 3: Exploratory Hole Location Plan – Business Zone North of AGresearch
Figure 4: Exploratory Hole Location Plan – Inland Port Zone and Business Zone to South
Figure 5: Geological Cross Section 1
Figure 6: Geological Cross Section 2
Figure 7: Geological Cross Section 3
Figure 8: Geological Cross Section 4
Figure 9: Geological Cross Section 5
Figure 10: Geological Cross Section 6
Figure 11: Geological Cross Section 7
Figure 12: Geological Cross Section 8
Figure 13: Groundwater Contour Plan – Residential Zone
Figure 14: Groundwater Contour Plan – Business Zone North AGresearch
Figure 15: Groundwater Contour Plan – Inland Port Zone and Business Zone to south
Figure 16: Soil Classification Chart
Figure 17: Moisture Content LL PL Chart – Residential Zone
Figure 18: Moisture Content LL PL Chart – Business Zone North AGresearch
Figure 19: Moisture Content LL PL Chart – Inland Port Zone
Figure 20: Moisture Content LL PL Chart – Business Zone South Inland Port
Figure 21: Compaction Data Chart
Appendices
Appendix A: Proposed Development Plans
Appendix B: Site Walkover Notes, Interview Findings and Photographs
Appendix C: Plans of Previous Ground Investigations
Appendix D: Shearwave Velocity Results
Appendix E: Listing of Organic Soils
Appendix F: Liquefaction Calculation Printouts – Residential Zone
Appendix G: Liquefaction Calculation Printouts – Business Zone North of AGresearch
Appendix H: Liquefaction Calculation Printouts – Inland Port Zone
Appendix I: Liquefaction Calculation Printouts – Business Zone South of Inland Port
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1 Introduction
Tainui Group Holdings Limited (TGH) and Chedworth Park Limited (CPL) are currently
undertaking investigations for the rezoning and structure planning of approximately 600ha of land
to the east of Hamilton as part of the Ruakura development.
The location and extent of the Ruakura Development area is shown on Figure 1.
This report presents the results of the geotechnical assessment reporting undertaken for the area
known as the “Stage 1 investigation area” of the Ruakura Development. Stage 1 investigation area
comprises proposed Residential Zones in the north-west of the site, a Business Zone north of the
AgResearch centre, an Inland Port Zone and a further Business Zone to the south. These zones are
shown on Figure 1.
Further investigation of each zone at the site will be necessary to form in depth geotechnical
assessments and essentially to confirm and detail the design measures required for the various
developments. These investigations may be required to be carried out over a number of phases.
The findings and opinions conveyed within this report are based on information obtained from a
variety of sources, which Opus believes are reliable. Nevertheless, Opus cannot and does not
guarantee the authenticity or reliability of the information it has relied upon from these sources.
All details of the proposed development are based on information available at the time of writing
this report.
1.1 Our Brief
TGH has engaged Opus International Consultants Ltd (Opus) to carry out the following:
1) Geotechnical field testing in the Stage 1 investigation area;
2) Geotechnical factual reporting of those investigations in the Stage 1 investigation area;
3) Geotechnical Interpretation of those investigations in Stage 1 investigation area;
4) Preparation of a Pavement Assessment for the Stage 1 investigation area;
5) Prepare a desktop “NES” contaminated sites assessment for the Ruakura development area.
6) Prepare a Geotechnical Summary Report for the Ruakura Development.
The Stage 1 investigation area comprises approximately a third of the full Ruakura Development
area. The development zones that make up the Stage 1 investigation area are shown on Figures 2 to
4.
Details of the geotechnical field investigation and laboratory testing carried out by Opus in the
Stage 1 investigation area are presented in our Factual Report dated 28th May 2013 (item 1 and 2 of
the above list).
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This report presents the results of the geotechnical assessment reporting undertaken for the Stage 1
investigation area of the Ruakura Development (item 3 of the above list).
A Pavement Assessment Report (item 4) is under preparation at the time of issue of this report.
The desktop “NES” contaminated sites assessment for the Ruakura development area (as defined
by the current TGH and Chedworth Park Limited ownerships) is presented in our Preliminary Site
Inspection Report dated June 2013.
A Geotechnical Summary was prepared and issued July 2013 (item 6 of the above list) and presents
the summary of the key geotechnical issues affecting the site.
2 Development Proposals / Activities
The Stage 1 investigation area is only approximately a third of the Ruakura Development area.
The zonation of the Ruakura Development area is shown on the plan entitled “Indicative areas for
Geotechnical Testing” prepared by others1, presented here in Appendix A. Also provided in
Appendix A is the “Land Ownership Plan2” and the “Preliminary Storm Water Flow Network and
Wetland Sizes Plan3”.
The Ruakura Development will involve residential, business (including Inland Port and industrial)
and knowledge (innovation park / commercial) zones.
More detail on the land use areas is provided on the “Land Use Allocation Plan” prepared by
others4 and presented in Appendix A.
Each proposed development zone is required to comply within the rules set out by the Proposed
District Plan prepared by Hamilton City Council.
Additional detail on the anticipated activities for the development zones is given below. This
should be read in conjunction with the “Land Use Allocation Plan” also presented in Appendix A.
2.1 Residential Zone(s)
The following approximate areas are proposed for general residential development (with 50%
impermeable surfaces) and medium density residential development (with 75% impermeable
surfaces):
• 36ha of general residential development and
• 42ha medium density residential development.
1 Harrison Grierson. Indicative Areas for Geotechnical Testing plan, drawing number 132241-GA204 Rev 1 and dated 07/12/12. 2 Harrison Grierson. Ownership plan, drawing number 132241-GA205 and dated 19/04/13. 3 Harrison Grierson. Preliminary Stormwater Flow Network and Wetland Sizes, drawing number 132241-GA105 Rev 3 and dated 12/12/12. 4 Land Use Allocation Plan, Ruakura. Boffa Miskell Limited, drawing number A08274_sk_004 dated 7th June 2013 Revision Z.
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The Proposed District Plan rules stipulate a maximum height for residential buildings of 10m for
both the general and medium density residential areas.
Therefore and for the most part, we anticipate that the development will comprise residential
properties 1 to 2 storey high and will include an infrastructure network (access roads, services) as
well as landscaped areas. Within this zone there is an area of proposed commercial / retail
buildings and these will likely comprise of shop type structures.
We also anticipate that the finished floor levels for these residential zones will be at or close to the
existing ground levels.
2.2 Business Zones (Employment / Industrial)
An area of approximately 192.4ha is proposed for employment/industrial/service centre
development (with 75% impermeable surfaces).
The Proposed District Plan rules stipulate a maximum height for buildings in this zone of 20m. It
also stipulates a maximum container stacking height of 6m.
The buildings in the Business Zones will likely include office / warehouse unit type structures with
an associated infrastructure network (access roads, services) as well as landscaped areas. We also
anticipate that the finished floor levels for these business zones will be at or close to the existing
ground levels.
2.3 Ruakura Logistics (Inland Port) Zone
An area of approximately 162.9ha is proposed for the Ruakura Logistics Zone development (with
75% impermeable surfaces). This zone includes an intermodal terminal (Inland Port) which will
have a phased development.
The Proposed District Plan rules state a maximum height for buildings in this zone of 20m. It also
stipulates a maximum container stacking height of 6m.
The buildings in the Logistics Zones will include warehousing type buildings with an associated
infrastructure network (access roads, services) as well as landscaped areas.
We understand from others5 that it is proposed to raise the ground level for the Logistics Zone
south of the East Coast Main Trunk Line to a level of 42.5m. This will broadly involve placing
between approximately 0.5m fill in the west and around 1m to 1.3m of fill in the east of the Zone.
2.4 Knowledge (Innovation Park / Commercial) Zone
An area of approximately 13.1ha is proposed for the Knowledge (Innovation Park / Commercial)
Zone which will have 75% impermeable surface.
The Proposed District Plan rules state a maximum height for buildings in this zone of 15m.
5 Harrison And Grierson, e-mail correspondence dated 29th April 2013 to TGH from Nigel Tse.
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The buildings in the Knowledge Zone will likely include office, commercial/ retail type buildings
with an associated infrastructure network (access roads, services) as well as landscaped areas.
2.5 Existing Rural Residential Zone
A 51.2ha area known as the ‘Existing Rural Residential Zone’ is located south of the Business Zone
in the vicinity of Morrinsville Road (SH26).
We are not aware of the development proposals, if any for this part of the site at this stage.
3 Site Description – Stage 1 investigation area
3.1 General Topography and Description
A general description of the topography across the Stage 1 investigation area is that it comprises
mostly open level pastoral and agricultural farmland, with slight rolling hills.
No significant boggy or marsh areas were observed at the site during our work although it is noted
that our site work has followed a particularly dry spell of weather. It is therefore possible that there
may be wet areas or areas that experience surface water ponding at the site, particularly during the
winter months, which we were unable to observe.
A number of associated farm buildings (both farm houses and outbuildings) are located on the site.
These outbuildings are generally barn or workshop type structures for storing crops, machinery,
maintenance equipment and tools.
There is a network of gravel surfaced ‘races’ which provide access to the field areas across the site.
A number of drainage ditches are also present across the site area, mainly along field boundaries.
Trees are sporadically located on the site but generally close to ditches or fence line areas.
The detailed site description presented below should be read in conjunction with Figure 1, together
with the walkover notes / interview findings and photographs presented in Appendix B. Many of
the details have been determined from both the walkover and discussions with representatives on
site.
3.2 Proposed Residential Zones in North West of Site
There are two proposed residential zones as part of the Stage 1 investigation area (See Figure 2).
The larger northern zone is owned and occupied by Chedworth Park Limited and is located to the
south of Greenhill Road, whilst the smaller zone is occupied by AGresearch and is located south of
Powells Road.
Both of these zones have a generally flat and level topography with slight rolling hills which is
typical for Hamilton.
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3.2.1 Northern Residential Zone
The main farm buildings and dairy operations are located approximately in the mid part of the
proposed residential zone. The buildings comprise barn and workshop type timber framed single
storey structures, in addition to a milking shed (Photos 1 to 3).
There is an ‘offal pit’ located between the buildings and with evidence of historic pits in the same
area (Photo 4). We understand that these pits are currently rarely used.
There are three effluent ponds to the north of the farm buildings and dairy shed (Photo 5).
A burial / burn pit is located in the north western part of the residential zone and has approximate
dimensions of 30m long by 10m wide by 4m deep (Photo 6). Historical pits extend in a 30m wide
corridor from the existing pit northwards by approximately 200m to 300m to the approximate
position of a field fence line. We were informed that no domestic refuse was disposed of in these
pits. When the pit reaches approximately 2m from the ground surface it is in-filled and a new
burial / burn pit excavated to the side.
The remainder of this residential zone generally comprises of open pasture land, with gravel
surfaced races providing access.
3.2.2 Southern Residential Zone
There are no farm structures on this part of the site and it mostly comprises open pasture land.
There is a cordoned off burial pit for waste timbers / vegetation in the south east part (Photos 7 and
8). The pit is approximately 30m long by 10m wide and 4m deep.
There is undulating ground south of the pit up to a fence line (Photo 9).
We were informed that a paddock area west of the current burial pit had formerly been used as
both a landfill and for solvent burning operations. This area was apparently the focus of
contamination remediation that was reported by Tonkin & Taylor. Enquiries are currently
underway to confirm this and to obtain copies of these reports if available.
3.3 Proposed Business Zone North of AGresearch
This zone is a generally flat and level topography with slight rolling hills which is typical for
Hamilton.
There is a proposed business zone located north of the main AGresearch centre (See Figure 3).
This zone is currently used for pasture to support livestock and also for growing plant produce.
A former laboratory building and associated greenhouse type outbuildings are located in the north
east of this business zone (photo 10).
Other structures present on this part of the site are generally farm type outbuildings such as hay
barns, sheds (photo 11).
The groundwater levels for this area have been indicated to us as being ‘quite shallow’ during
winter months, perhaps reaching 0.5m below ground level.
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3.4 Proposed Inland Port Zone
This zone is a generally flat and level topography with slight rolling hills which is typical for
Hamilton.
A proposed inland port is located in the southern part of the Stage 1 investigation area (see Figure
4).
That part of the Inland Port Zone North of Ruakura Road is occupied by AGresearch, and the area
to the south of Ruakura Road is occupied by a dairy farm.
There are a number of farm and private residential type buildings in the northern part of this zone
(photo 11). There is also small orchard located in the northern part of the site to the west of
Percival Road (Photo 13).
There are further farm and private residential type buildings in the southern part of this zone
(photo 14).
The majority and remainder of this part of the site is pasture land for livestock for dairy farming.
3.5 Business Zone South of Inland Port
This zone is a generally flat and level topography with slight rolling hills which is typical for
Hamilton.
There is a proposed business zone to the south of the Inland Port (Figure 4).
This business zone is occupied by a dairy farm.
There are a number of farm type outbuildings and commercial type buildings in the western part of
this zone (Photo 15), whilst the majority and remainder of this part of the site is pasture land for
livestock for dairy farming.
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4 Desk Study
4.1 Published Geological Information
From our review of the available published geological map6 for the area the site was anticipated to
be underlain predominantly by rhyolitic current bedded sands and gravels interbedded with peats
and pumice silts and sands of the Hinuera Formation.
The Hinuera Formation was deposited in the late Pleistocene Epoch, is up to 90m thick and is the
result of deposition of typically volcanic materials from the Taupo Volcanic Zone by a braided
ancestral Waikato River. The surface of the Hinuera Formation features a ridge and swale micro-
topography with well drained soils typically being found on the ridges and poorly drained soils
occurring in the swales.
The pumiceous silts, sands and gravels with interbedded peat and rhyolitic pumice of the Walton
Subgroup (which is generally under the Hinuera Formation) is indicated to be locally present at
ground level and to be similar in composition to the Hinuera Formation.
Swamp deposits comprising soft dark brown to black organic rich mud, muddy peat and woody
peat are shown on the eastern part of the Ruakura Logistics Zone.
Previous work by others7 indicates that basement rock may be encountered at a significant depth
below the site of up to 440m depth.
4.1 Near Surface Soils Information
Previous work by others8 states that there is a potential for near surface peat soils to be present
within the following areas:
• the eastern part of the Business Zone north of AGresearch,
• within the eastern part of the Inland Port Zone and
• within the eastern part of the Business Zone to the south of the Inland Port.
4.2 River Flood Hazard Map
The site is not shown to be within a river flood hazard area according to the river flood hazard
maps publically available from the Waikato Regional Council website9.
6 1:25000 Scale Geological Map Sheet N65/2, ‘Hamilton’, NZ Geological Survey, 1965 Geology of Hamilton Area 7 Tonkin & Taylor, Presentation on “Ruakura Estate Development, Geotechnical Aspects” 8 Report for Tainui Developments by Dr Richard Chapman, Soil and Land Evaluation, December 2001. 9 1:50,000 broadscale Hamilton South / East, Waikato Regional Council web site http://www.waikatoregion.govt.nz/Services/Regional-services/Regional-hazards-and-emergency-management/River-flooding/Broadscale-information/
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4.3 Faulting
The nearest fault to the site shown on the GNS web site10 to be the Kerepehi Fault located in the
Hauraki Graben approximately 40km east of Hamilton. This fault has a recurrence interval of
5,000 to 10,000 years, has a low slip rate (0.1mm to 1mm per year) and the last event is thought to
have been between 160yrs to 1000ys ago. There are no active faults indicated by the geological
information or the GNS website to be on or within close proximity to the Ruakura Development
area.
4.4 Previous Ground Investigations
There have been a number of ground investigations at or close to the Stage 1 Investigation area and
these are described as follows.
4.4.1 Investigation for the Hamilton Ring Road
A ground investigation and a Geotechnical Factual Report11 for Hamilton City Council has been
prepared by others for the Wairere Drive – Crosby Road to the Cambridge Road project (now
Hamilton Ring Road). Copies of the site investigation location plans are provided in Appendix C.
The exploratory holes listed below are located close to the west boundary of both the proposed
Residential Zone in the north of the site and the Business Zone north of AGresearch.
Locations beyond west boundary of Residential Zone
• Boreholes – BH1, BH2
• Test Pit – TP1
• Auger Scala Holes – AH1, AH2, AH3, AH4.
Locations beyond west boundary of Business Zone North of AGresearch
• Boreholes – BH7, BH8
• Test Pits – TP5, TP6, TPBH8
• Auger Scala Holes – AH18, AH19, AH21, AH22, AH23, AH24.
Laboratory testing of selected soil samples was also carried out and included consolidated
undrained triaxial compression testing on push tube samples obtained from BH8.
4.4.2 Opus Investigation for the Waikato Expressway
Opus have carried out a number of exploratory holes on behalf of NZTA (boreholes, cone
penetrometer tests, test pits and Auger Scalas) over a number of phases along the proposed route
10 New Zealand Active Faults Database. GNS Science website www.gns.cri.nz/Home 11 Geotechnical Factual Report by Aecom, dated 21 July 2010 and referenced 60102054, revision 1.
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of the Hamilton Section of the Waikato Expressway12 east of the TGH site. Copies of the site
investigation location plans are provided in Appendix C.
The exploratory holes located close to the east boundary of the Inland Port Zone and the Business
Zone to the south are listed as follows.
Locations beyond east boundary of Inland Port
• Boreholes – 304, BHT1
• Test Pits – 307, 308
• Auger Scala Holes –306, 308, AST1
• Cone Penetrometer Tests – 304, 306, 308, 309, 310, CPT T2, CPT T4,
Locations beyond east boundary of Business Zone South of Inland Port
• Test Pits – 311, 313, TP T1
• Auger Scala Hole –ST1
4.4.3 Ruakura Preliminary Geotechnical Investigation
A preliminary geotechnical investigation and report has been prepared by Cardno13 for the Ruakura
site. Copies of the site investigation location plans are provided in Appendix C.
The report focussed on the proposed infrastructure at the site and therefore was targeted for the
proposed spine road and the stormwater areas of the project area (encompassing both Stage 1 and
future development areas).
The following exploratory holes are located within or close to the Stage 1 development zones.
Residential Zone
• Test Pits – TPS1 to TPS10, TP24 to TP27, TP30
Business Zone North of the AGresearch
• Test Pits – TPS10 to TPS12, TP31
Inland Port Zone
• Test Pits - TPS15 to TPS23, TP52 to TP55
12 Opus Geotechnical Factual Report, Stage 1, Waikato Expressway, Hamilton Section, Report number 231695.00/c10346 13 Cardno Preliminary Geotechnical Report, Ruakura Estate, Hamilton, dated October 2011 and referenced NZ0710030.
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Business Zone South of Inland Port
• Test Pits – TPS19 to TPS23, TP68 to TP71.
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5 Stage 1 Site Investigation
Opus scoped, managed and reported14 on the investigation for the proposed Stage 1 area.
5.1 Exploratory Holes
The geotechnical field work was carried out in April 2013 and comprised:
• 12 Rotary Cored Boreholes
• 16 Test pits with Scala Penetrometer Testing
• 43 Auger / Scala Penetrometer Tests (SCPT)
• 3 Seismic Cone Penetrometer Tests (CPT)
• 5 Cone Penetrometer Tests
• 12 Permeability tests in borehole piezometers
• Groundwater Monitoring
The logs, test data and groundwater monitoring results of the Stage 1 site investigation are
presented in the Geotechnical Factual Report.
The exploratory hole locations are presented on Figures 2 to 4.
A total of three seismic cone penetrometer tests (CPTs) were carried out and the data processed by
Opus Engineers to determine the shearwave velocity with depth profile of the soils. The processed
results are presented in Appendix D.
5.2 Insitu Field Tests
The standard penetration test (SPT) results obtained from the boreholes generally recorded lower
values than may expected for the silt soils in comparison with the consistencies inferred from the
CPT and Scala test results.
The SPT ‘N’ values for the sand soils generally compare quite well with those inferred from the CPT
data.
Peak and residual shear strength values shown from the shear vane tests carried out in selected
boreholes indicate that these soils are moderately sensitive to sensitive and likely to be silt soils
rather than clays.
In general the interpreted shearwave velocities from SCPT101 to SCPT103 compare well with the
cone resistance recorded by the CPT, with an increase in velocity with increased cone resistance.
High variance of the shearwave results generally follows the variation between the interbedded
sand and silts present at the site.
Shear wave velocities of generally between 100m/s through to 230m/s were recorded at the
locations tested.
14 Opus Geotechnical Factual Report, report number G3121, Ruakura Development Stage 1: Geotechnical Investigation, dated May 2013.
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5.3 Laboratory Testing
Laboratory testing was specified by Opus and was carried out by Opus Laboratories and comprised:
• 6 Oedometer Consolidation
• 6 Organic Content
• 10 Atterberg Limits – Liquid limit, plastic limit, plasticity index.
• 6 New Zealand Standard Compaction
• 10 Californian Bearing Ratio (CBR) un-soaked
• 10 Californian Bearing Ratio (CBR) soaked
• 10 Particle Size Distribution (hydrometer)
The laboratory test results are presented in the Geotechnical Factual Report.
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6 Soil Conditions Encountered
In summary, all the exploratory holes for the various zones encountered topsoil (typically 0.05m to
0.25m thick) over variably interlayered silty sand and sandy silt soils with varied quantities of sand,
silt, gravel and organic material to the full depth of the investigation (30.45m).
Fill materials were encountered in BH112 to approximately 7m depth, comprising and sandy silt
and sand with timber, nails and steel wire fragments.
The soils at the site have been found to be highly variable both vertically and laterally, with no
significant recognisable pattern to the geology between exploratory hole locations.
Geological cross sections were prepared as part of the Stage 1 investigation area and show the high
variability of the soils present in the upper 7m of soil across the site. These are reproduced here as
Figures 5 to 12, and the locations of the sections are shown on Figures 2 to 4.
The rapid lateral and vertical variation in the sand and silt soils encountered is typical of deposition
of a braided river environment and is a feature of the Hinuera Formation. Soils with variable
contents of organic matter were found in a number of exploratory holes, varying from silts and
sand with some organic material to true buried peat soils. The latter were proved at depth.
6.1 Fill Material
Fill comprising of soft dark brown sandy silt and medium dense grey sand is present at BH112 to
7m depth. These materials contain variable quantities of pumice gravel and locally steel wire.
A piece of wire was noted in the core retrieved at 9.50m but within materials logged as natural grey
sand soils. We believe this piece of wire was lodged in the barrel upon extraction of the previous
section of core.
6.2 Topsoil
Topsoil has generally been encountered across the site from ground level to between 0.05m to
0.25m depth.
6.3 Strata of the Hinuera Formation
The Hinuera Formation soils are highly variable between fine grained silt and sands and with some
of these layers having an organic content.
The high vertical and horizontal variation between silts, sands and various organic soils is likely
related to the alluvial fan mode of deposition of these soils, and is typical of soils of the Hinuera
Formation.
6.3.1 Fine Grained Soils
The fine grained soils generally comprise yellowish brown to grey and orange silt with varying
quantities of sand, gravel and clay. In general, the sand was fine to medium grained.
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The gravel within the silt soils have been noted to be pumice and heavily weathered so that some
breaks down under heavy finger pressure. This means that these soils have the potential to break
down significantly during compaction.
Where encountered near surface, the silts are generally either soft or firm in the upper 1m,
generally becoming soft below this depth. It is possible that some of the upper silt soils near
surface may be weathered air fall ash deposits.
In the field these soils are described as mostly non plastic to slightly plastic.
6.3.2 Granular Soils
The sand soils are generally yellowish brown and grey either loose or medium dense with varying
quantities of silt and gravel. The sand is mostly fine to medium grained.
The gravel within the silt soils have been noted to be pumice and are heavily weathered so that
some break down under heavy finger pressure. This means that where these soils have the
potential to break down significantly during compaction.
6.3.3 Organic Soils
Organic soils were encountered over a large variation of depth (see table in Appendix E).
Generally, organic soils recorded near surface (upper 4m) across the Ruakura Development Stage 1
Zones were soft silt or loose sand soils, often described as ‘organic’ or with fibrous / wood
fragments. Whilst these soils are organic, they are not as highly compressible and at risk of long
term settlements as ‘true’ peat or silty peat soils.
The only peat soils observed at the site were organic silt / peat recorded at depths greater than
13.5m and these were mostly described as stiff / hard, although some very soft layers were
recorded.
The organic silt soils encountered at the site do not match with the ‘silty peats’ that were
anticipated from the Ruakura Soil Map information reviewed. However, bearing in mind the large
spacing between exploratory holes there is a risk that such silty peats may be present elsewhere on
the site.
6.4 Bedrock
Bedrock was not encountered to the full depth investigated of 30.45m. This is as expected from the
desk study information which indicates bedrock may lie at over 400m depth.
6.5 Comparison with Previous Ground Investigations
The soils encountered on site generally compare well with the Hinuera Formation soils proven in
the investigations to the east and west of the site.
Allophane content tests were carried out on near surface soil samples obtained for the Waikato
Expressway investigations and these all returned allophane contents of less than 5%, indicating the
soils tested were probably not derived from ash.
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The soil descriptions and recording of the Scala test results by Cardno are not in accordance with
New Zealand standards. This makes comparison of their results difficult to compare, however, the
exploratory holes generally match the mixed interlayered silts, sands and organic layers.
Organic soils identified by Cardno are listed as follows:
• TP26 – 1.60m to 1.95m - “Topsoil like material”
• TP52 – 2.10m to 2.40m – “Very dark PEAT”
Significant fill was also identified in TP69 to 1.70m depth and described as an old farm pit.
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7 Groundwater
To determine the possible presence of perched water tables, a combination of shallow and deep
piezometers has been installed in the boreholes at the site. The response zones of each piezometer
were separated by a silt or low permeability soil. Groundwater monitoring was carried out to
record the water levels in these piezometers in addition to those piezometers installed by others
within the Stage 1 zones.
The groundwater monitoring was carried out following a period of drought and as such the
recorded levels may not represent the shallowest levels that may be expected, especially winter
levels. Groundwater levels are expected to vary significantly on a seasonal basis.
7.1 Shallow Piezometers
The groundwater levels from the shallow piezometers installed across the site have been used to
formulate the groundwater contour plans presented in Figure 13 to 15.
Recorded groundwater monitoring results are presented in the Factual Report. Groundwater levels
from the shallow piezometers and the inferred site wide flow direction is given on Table 1 below for
each zone.
Location General Variation of Groundwater depth across the zone (m begl)
General groundwater flow Direction
Residential Zone 1.0m to 4.0m North-West Business Zone North of
AGresearch 1.0m to 3.5m West
Inland Port Zone 2.0m to 4.0m North-West Business Zone South of
Inland Port 2.0m to 4.5m North-West and South-East
Table 1: Groundwater levels and flow direction, May 2013
The Waikato River is located to the west of the site and therefore overall groundwater flows are
expected to be drawn down towards the river. In addition, the Mangaonua Gully is located to the
south east of the Business Zone south of the inland port, therefore groundwater levels are expected
to be locally drawn down to this direction in this part of the site. The results for the shallow
groundwater levels are consistent with these expectations.
We have compared the groundwater monitoring results with those carried out by others15 which
have included groundwater monitoring through the winter period. The following bullets
summarise our review of the results;
• Groundwater levels in the Residential Zone at the time of our investigation were at a level
approximately 1m deeper than may be expected from levels typically observed towards the end
of the winter period.
• Groundwater levels in the other zones at the time of our investigation are at approximately 2m
deeper than may be expected from levels typically observed towards the end of the winter
period.
15 Groundwater monitoring results carried out on the Cardno Installations by Harrison and Grierson through the period 10/10/2011 to 11/2/2013. Project reference 1520-132241.01
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7.2 Deep Piezometers
Most deep piezometers installed recorded groundwater levels slightly lower than those recorded for
the shallow piezometers.
The general difference in water levels from the piezometers is given in Table 2 as follows.
Location Borehole location
Deep piezo water level below shallow piezo
General trend of monitoring results between deep/shallow
Residential Zone BH101 1.00m to 1.50m Deep rising, shallow falling Business Zone North of AGresearch
BH102 BH103
0.00m to 0.50m 2.75m to 3.25m
Deep falling, shallow falling / rising Deep falling, shallow falling / rising
Inland Port Zone BH104 BH105 BH106 BH107 BH108 BH109
0.75m to 1.25m 0.75m to 1.25m 0.50m to 1.00m 0.50m to 1.00m 0.50m to 1.00m 0.25m to 0.75m
Deep and shallow falling Both deep and shallow fall and rise Both deep and shallow fall and rise
Deep and shallow falling Deep and shallow rising Deep and shallow falling
Business Zone South of Inland Port
BH111 BH112
3.75m to 4.25m 0.50m to 1.00m
Deep rising, shallow falling Deep rising, shallow falling
Table 2: Difference and general trend between deep and shallow piezometers
From the piezometer data it appears that there may not be a separate series of perched water tables
on the low permeability silt layers observed, and that these are too discontinuous to have anything
more than very local effects.
Only those piezometers in BH103 and BH111 generally show significant variation between the
upper and lower piezometers suggesting that at these locations there may be an upper perched
water table.
7.3 Soakage / Permeability Testing
Preliminary soakage tests were performed by Cardno in areas identified for potential storm water
retention by others (see ‘Preliminary Storm Water Flow Network and Wetland Sizes Plan16 in
Appendix A). These soakage tests were generally carried out near surface (in the upper 2m)
draining into either fine or coarse grained soils.
16 Harrison Grierson. Preliminary Stormwater Flow Network and Wetland Sizes, drawing number 132241-GA105 Rev 3 and dated 12/12/12.
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The soakage rates recorded for areas within the Stage 1 investigation area are presented in Table 3
below:
Soakage Rates Recorded Location Fine Grained soils (fine
silty sand/silts/clays) Coarse grained soils (coarse sands/gravels)
Stormwater Area 9 - Residential Zone NW site
26mm/hr -
Stormwater Area 7 Business Zone north of AGresearch
7mm/hr & 14mm/hr -
Stormwater Area 4 Inland Port Zone 16mm/hr & 18mm/hr 1101mm/hr Stormwater Area 2 Business Zone South of Inland Port
61mm/hr 1,058mm/hr
Table 3: Soakage test results by Cardno
Soakage rates recorded by Cardno (investigation plans presented here in Appendix C) were affected
by shallow groundwater levels identified as the test pits were carried out.
Permeability testing of the near surface sandy soils was undertaken within the boreholes carried
out within the Stage 1 investigations by Opus, the locations of which are presented on Figures 2 to
4. In a number of the tests the permeability could not be calculated due to flow rates being too fast
to be able to be able to establish a head. From those tests where permeability was calculated,
results of between 1.0x10-5m/s to 5.6x10-8m/s were recorded.
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8 Laboratory Test Results
Laboratory testing of selected soil samples has been carried out with the aim of addressing the
likely geotechnical issues associated with the site and sufficient to highlight potential design risk.
The geotechnical testing aims was establishing the following:
• Settlement characteristics of the near surface soils
• Potential for organic soils and their properties
• Potential for the re-use of near surface soils as fill
• Pavement design parameters of near surface and re-moulded soils
8.1 Oedometer Consolidation Tests / Organic Contents
A total of 6 oedometer tests were carried out on selected soil samples for across the site. The
organic content tests were carried by the loss on ignition method. Results are listed on Table 4.
Location Depth Range of Volume Compressibility (Mv) at pressures greater than overburden
Recorded Organic Matter - %
Recorded Water content
BH101 18.00-18.60m 0.15-0.26m2/MN 9% 114% BH103 3.00-3.60m 0.28-1.2m2/MN 5% 154% BH105 10.50-11.10m 0.03-0.09m2/MN 8% 43.6% BH107 12.50-13.10m 0.02-0.03m2/MN 0% 50.1% BH108 17.00-17.50 0.06-0.10m2/MN 7% 42.9% BH110 0.50-1.10m 0.03-0.13m2/MN 1% 17.6%
Table 4: Results of Oedometer / Organic Content tests
These data indicate that as we would expect those soils with the highest organic content are the
most compressible.
8.2 Classification Testing on Fine Grained Soils
Classification testing was carried out on 10 samples selected over a range of depths across the site.
The fine grained soils tested predominantly classify as silts of high plasticity (Figure 16). Four
samples classify as low plasticity but are marginal to this line.
The plots of moisture content, liquid limit, plastic limit profiles with depth are presented for each
zone on Figures 17 to 20. Key points from these plots are:
• Moisture content with depth generally varies significantly with no general increase with depth
determined as may be anticipated for these soils. We consider this most likely related to the
pumice of the soils or the organic content. Pumice and organics can hold on to moisture in
voids or lattice and this may affect the actual water content through the soil.
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• Soils that have a moisture content that is close to or above their liquid limit may be expected to
behave as a liquid. The exception may be where the moisture content is not representative due
to water held by organics or pumice in the soils.
• With the exception of the shallow sample tested at BH103 (3m) in the Business Zone north
AGresearch and the sample at TP111 (1.7m) in the Inland Port Zone, the moisture contents
recorded are below the liquid limit. On the basis that these two samples are not described as
organic, it is likely that the water contents may be recorded higher than it is due to the sand
particles being pumice.
8.3 NZ Standard Compaction Tests
NZ standard compaction tests were carried out on 6 soil samples. The compaction data curves are
presented on Figure 21.
The range of maximum dry density ranges from 1.21t/m3 through to 1.71t/m3 and this is considered
to be due to the variation in soil types tested, in addition to the pumicious nature of these
materials. On this latter note, a number of the pumiceous gravels described in the investigation
were noted to break down under finger pressure and this may to some extent may break down
during compaction.
8.4 Particle Size Distribution Tests
We have adjusted field soil descriptions to match the results of particle size distribution tests.
On this latter note, a number of the pumiceous gravels described in the investigation were noted to
break down under finger pressure and this may also affect the grading results as the gravels may
break down during the sieving action of the test.
8.5 Re-Moulded CBR Tests
The results of un-soaked and soaked CBR testing at natural moisture content of near surface soils
are presented on Table 5 below. All samples recorded
Test Pit
Depth
(m begl) Description
Un Soaked
CBR %
Soaked
CBR %
TP102 0.50m Silty SAND 30 25
TP103 0.15m SILT 0.5 0.5
TP105 1.00m SAND, minor silt and clay 20 17
TP107 0.90m SILT 0.5 0.5
TP109 0.50m Silty SAND 25 12
TP110 0.50m Silty pumiceous SAND 25 8
TP112 0.60m Silty pumiceous SAND 25 7
TP114 0.15m SILT 25 9
TP115 0.30m SILT 20 7
TP116 0.50m SAND 25 10
Table 5: Summary of CBR test results
Silt soils recorded a range of un-soaked CBR values of 0.5% to 25%, whilst the soaked CBR values
for these soils is 0.5% to 9%.
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The sand soils recorded un-soaked CBR value is 20% to 30%, whilst the un-soaked CBR values for
these soils are 7% to 25%.
From these we can clearly determine that for both soil types there is a great sensitivity to changes
in moisture content that may have significant influence on the soil earthworks and pavement
properties.
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9 Brief and Development Proposals
9.1 Brief
Our brief and the main focus of our geotechnical interpretation are to provide a commentary to
cover:
1) Settlement risks
2) Liquefaction potential
3) Extent of peat and other soils
4) Preloading requirements
5) Other reporting pertinent to the Stage 1 proposed development.
In our reporting we have also included other site wide engineering considerations such as
foundations, pavements and recommendations for further work.
The following is a more detailed discussion on our understanding of the likely development
proposals.
9.2 Development Proposals
9.2.1 Fill and Settlement
We understand from others17 that it is proposed to raise the ground level for the Inland Port Zone,
to a level of 42.5m. This will broadly involve placing around 0.5m fill in the west part and around
1m to 1.3m of fill in the east part of the Inland Port Zone.
We are not aware of the details of operations planned for the other zones of the Stage 1
development and we generally anticipate most of the developments to be at or close to existing
ground level.
Settlement occurs due to the load of the fill displacing groundwater and compressing the soils
beneath. The rate at which settlement occurs will also affect the time required for construction.
Generally, most settlement needs to be complete prior to laying pavements or erecting structures to
reduce the risk of damage due to settlement particularly differential settlement.
For the Inland Port zone, the pavements and site structures are expected to be particularly
sensitive to differential settlement.
Distortion or deflexion of structures and infrastructure of greater than 1/50018 would likely lead to
cracking in walls and partitions.
17 Harrison And Grierson, e-mail correspondence dated 29th April 2013 to TGH from Nigel Tse. 18 Table 2.7, pp59. Foundation Design & Construction, MJ Tomlinson, 6th Edition.
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9.2.2 Fill Sources
We have carried out a nominal amount of laboratory soils testing to assess the suitability of near
surface soils for re-use at the site.
However, we are not aware of any major cuts proposed for developing the site and on consideration
of the soil types and high groundwater levels we do not recommend any general lowering of the
ground level.
This means that we anticipate that an external source of fill materials will be required in order to
meet with the fill proposals for the site.
9.2.3 Floor Levels
With the exception of the Inland Port Zone which will have a floor level of 42.5m, we anticipate
that the finished floor levels for the residential and business zones will be at or close to the existing
ground levels.
9.2.4 Foundations
We have assumed the following for our discussion on foundation options at the site:
• Residential properties will generally be 1 to 2 storeys high and that these will typically have
shallow reinforced raft type, short timber piles or traditional shallow strip foundations.
• Buildings in the Inland Port Zones will be warehouse type structures that may also be 1 to 2
storeys high and that these will typically have a combination of pad and strip type footings or
have reinforced shallow raft foundation. The Inland Port may also require a network of pad
type footings to support stacked containers and machinery used for the movement of these
containers.
• Buildings in the Business Zones will be 1 to 2 storeys high and that these will typically have a
combination of pad and strip footings or have a reinforced shallow raft foundation.
We have also assumed that site wide drainage will be put into place so that groundwater levels do
not rise above 0.75m below ground level.
There will be higher loads imposed on foundations where the building height increases. At the
detail design stage this may mean there comes a point where traditional shallow pad, strip or
reinforced raft type foundations become uneconomical in comparison to pile type solutions. Piles
will need to be designed to cope with the effects of liquefaction and this may mean that for some
structures a deeper ground investigation to that already undertaken may be needed to facilitate
detailed design of piles.
As may be expected, the larger a building and building having more people (seismic Importance
Level 3) may need more robust foundations than buildings with a lower seismic level within the
same development zone. These may need a stiffer raft or piled foundations and the need for this
will need to be assessed at the detailed design stage once the actual form of the development is
known.
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9.2.5 Pavements
A separate pavements report is currently being prepared for the Inland Port Zone.
We have provided here a general commentary on the anticipated CBRs that may be assumed for
road pavements across the Stage 1 investigation area.
9.2.6 Stormwater Disposal
We understand that stormwater drainage of the site is being undertaken by others and therefore we
have only provided a general summary for this report.
We have assumed that site wide land drainage will be put into place so that groundwater levels do
not rise above 0.75m. This will ease excavations for foundations and associated underground
services and infrastructure.
Preliminary design of stormwater measures will need to follow the Hamilton City Council rules for
stormwater management, both for the stormwater drainage of roads and also drainage from
buildings.
The Hamilton City Council has a general preference for stormwater soakage options that involve
infiltration to the ground (e.g. soakage wells for roof drainage).
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10 Interpretation – Calculation Methodology
10.1 Potential Fill Material & Induced Settlements
10.1.1 Use of near surface site won soils as fill
As discussed in 9.2.2, we do not recommend a general lowering of the ground level and this means
that an external source of fill will be required for the Inland Port Zone. We have however carried
out nominal compaction testing of the near surface soils across the site to explore if re-use of
excavated spoil could be a possibility.
General acceptance criteria for re-use of the near surface soils that we have adopted include:
For granular soils
• A defined moisture content band derived from the laboratory compaction results. This is from
the optimum moisture content through to a moisture content that gives 95% maximum dry
density (MDD) and less than 5% air voids.
• CBR of compacted samples greater than 2.
For fine grained soils
• That drying of silt and clay soils to reduce water content is limited to about 10% in the
temperate Waikato climate.
• Natural water content less than 10% higher than the plastic limit.
• A Liquidity Index of less than 1.
• A minimum undrained shear strength of between 70kPa to 150kPa (i.e. stiff consistency). This
is required to allow contractors to operate plant over the soils without rutting.
Re-Use of Soils Assessment
Laboratory testing to date for the Stage 1 investigations indicates that the site won fine grained
Hinuera soils are significantly wet of their optimum moisture content and would require significant
drying to become re-useable as structural fill.
The granular soils are dry of optimum moisture content (OMC) and have a wide range of OMCs
(Figure 21). These will need some wetting prior to re-use as structural fill. In this case quality
control during construction will likely be difficult and costly.
Using conventional earthworks practices for drying of silt and clay soils (e.g. sun and wind
exposure or lime/cement treatment), sun / wind drying effort is generally limited to 10% moisture
loss for the temperate Waikato climate. The laboratory test results to date indicate that drying in
excess of this may be needed.
Another option is that of mixing the site won fine grained and granular soils. This would be
extremely difficult to manage and ensure quality control for structural fill. We consider that such
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an approach to be very high risk and would need significant additional quality control measures
during construction.
In practice, separating out the fine grained and coarse grained materials in order to stockpile and
treat may also prove to be impractical during construction because of the highly variable nature of
the Hinuera soils, both vertically and horizontally.
From the test data and our experience of these soils we believe that although site treatment to dry
the fine grained soils by either sun / wind or the addition of lime or cement is feasible, it carries
significant weather risk during construction which could delay site work and increase costs.
Spreading of the material will require space to spread it in thin layers and time to turn and double
handle the soils. This is an option but carries risks and additional costs.
To provide some guidance on compaction factors, we have compared the compacted bulk density
with the undisturbed bulk densities from laboratory tests and the following average volume
changes are observed for both granular and fine grained soils:
1) Granular soils – Compacted soils show generally 5% to 10% volume reduction
2) Fine grained soils – Compacted soils show generally 10% to 15% volume reduction
It is important to note that the gravels within the Hinuera soils are pumice and were observed to
crumble under finger pressure. This will need to be borne in mind where such soils are being
compacted in order to avoid overworking these soils and changing the soil structure and behaviour
reducing the suitability for re-use.
Site won soils may be considered for landscaping use.
10.1.2 Settlement Calculations
The settlement calculations we have carried out in this appraisal should be treated as indicative /
preliminary at this stage and further work (for example a trial fill with settlement monitoring) is
recommended to confirm the actual design and any mitigation measures necessary during
construction.
We have estimated settlement using the classic One-dimensional Consolidation Method as set out
below:
�� = � ��∆σ�′��
�
Where:
mv is the coefficient of compressibility (m2/MN)
dz = Layer thickness
∆��′ = Change in the effective stress in the centre of the soil layer
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Estimates of mv were taken from the following correlation with CPT cone resistance:
�� = 1����
Where αs is the correlation factor typically 3.5 for silts and 3 for Sands.
We have carried out a comparison of mv results calculated using the CPT data and those obtained
from laboratory testing. We compared the mv results calculated for soils of similar descriptions
between both the CPT and oedometer tests at the depths tested in the Inland Port Zone.
For all cases, the mv range recorded from the oedometer results from the borehole samples
compared well with the CPT derived values of mv.
10.2 Foundation Bearing Capacity
We have assessed the site investigation findings to determine if the soils at the site could meet with
the ultimate bearing capacity requirements of not less than 300kPa as defined in both the
NZS3604:2011 for Timber framed buildings19 and also NZS 4229:2013 for Concrete Masonry
Buildings20.
The above standards set out the minimum blows per 100mm for Scala penetration tests beneath
the underside of the proposed footings that meet with the minimum ultimate bearing capacity and
these are broadly summarised as follows:
i. 5blows/100mm to a depth twice the footing width.
ii. 3blows/100mm or greater below a depth twice the footing width.
10.2.1 Generic Designs in Stage 1 Development Areas
Only two Auger Scala locations carried out within the Stage 1 Residential area (AS104, AS111) met
with the requirements of NZS3604:2011 for timber framed buildings for an ultimate bearing
capacity requirement of not less than 300kPa.
Also only three Auger Scala holes carried out within the Stage 1 Inland Port area (AS128, AS133
and AS134) met with the requirements of NZS 4229:2013 for Concrete Masonry Buildings for
ultimate bearing capacity requirements of not less than 300kPa.
Further investigation will be required to confirm and define the extent of those areas where a
generic foundation design in accordance with the above quoted standards can apply.
10.2.2 Specific Engineering Design
Site specific engineering designs will be required where the site does not conform to the above
requirements for generic designs and this will therefore apply to most of the Stage 1 investigation
area.
19 New Zealand Standard NZS3604:1999, Timber Framed Buildings, Incorporating Amendments 1 and 2 20 New Zealand Standard NZS 4229:2013, Concrete masonry buildings not requiring specific engineering design
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We have undertaken a preliminary calculation using Verification Method B1/VM4 by the Building
Industry Authority to determine the ultimate bearing strength for 0.30m, 0.45m and 0.60m wide
strip footings that are centrally and uniformly loaded founded at 0.3m, 0.50m and 0.75m depth
within the residential zone.
For the business and inland port zones we have undertaken a preliminary calculation using
Verification Method B1/VM4 to determine the ultimate bearing strength for 0.30m, 0.45m and
0.60m wide strip footings that are centrally and uniformly loaded founded at 0.3m, 0.50m and
1.0m depth. We also undertook calculations using VM4 to determine the ultimate bearing strength
for 0.50m, 1.00m and 2.00m wide pad footings that are centrally and uniformly loaded founded at
0.50m and 0.75m depth.
10.3 Foundation Settlement
We have not calculated individual settlements for the above footings as these are highly dependent
on footing size, depth and nature of the underlying soils.
In general terms we believe that provided the design bearing strength adopted is no more than a
third of the soils ultimate bearing strength then settlements should be less than 25mm. However,
this needs to be confirmed at the detailed design stage.
It may be possible to develop a generic piled or raft foundation for each house / structure type in
the Stage 1 investigation area at the detailed design stage.
10.4 Seismic Characteristics
10.4.1 Proposed Structure Importance Levels
At present the exact form of the various development zones is not known.
We have generally assumed that one to two storey type buildings are anticipated for the proposed
residential zone in the north west part of the site to be predominantly ‘Importance Level 2 type
structures’ as defined by NZS 1170.0 200221. We also assume that each of the buildings in the
proposed business zones will have occupancy of less than 5000 people, and a building footprint
area of less than 10,000m2.
In addition, whilst we anticipate most structures at the site will likely be 1 to 2 storey height, the
Council District plan rules will allow buildings to be constructed up to 10m height in the residential
zone, 20m height in the business / inland port zones and 15m in the knowledge zone.
On the above assumptions we consider such buildings in these parts of the development to be
‘Importance Level 2 type structures’.
Warehouse type buildings within the proposed inland port area will likely exceed a building
footprint of 10,000m2. However, such structures are unlikely to have multi or high occupancy
(over 5000 people) and therefore we also consider these warehouses to be ‘Importance Level 2 type
structures’.
21 Standards Australia/New Zealand; AS/NZS 1170.0:2002. Structural Design Actions – Part 0:General Principals.
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However, we understand that it is possible that there may be structures or facilities proposed at the
site that:
• May have an area where 300 people or more could congregate
• May have college or adult education facilities with a capacity of more than 500 people.
In accordance with NZS 1170.0 2002, such structures are ‘Importance Level 3 type structures’ and
the implication here is that the assumed return period for a seismic event used in design is
increased from 1:500yr to 1:1000yr and increases the assumed peak ground acceleration that needs
to be adopted for liquefaction and design.
As discussed above, the form of development will affect the seismic importance level that can be
assumed in the assessment and design process. The effect of this is that the higher the seismic
importance levels then more strengthening may be required to mitigate the effect of earthquake
loading.
10.4.2 Design Earthquake Return Period
Based on a design life of 50 years for all proposed structures at the site, the design annual
probability of exceedance for the ultimate limit states is 1:500yr for importance level type 2
structures and 1:1000yr for importance level type 3 structures.
10.4.3 Location Seismic Hazard
Hamilton has a relatively low seismic hazard with a zone factor of 0.16 according to NZS 1170.5 and
this has been adopted for design. There are no known active faults within 20 km of the site.
10.4.4 Site Sub-Soil Class
We have classified this area as a deep soil site (Class D) according to NZS 1170.5. None of our
investigations encountered bedrock and from our understanding of the regional geology, we expect
bedrock would be more than the 45m maximum soil depth limit for the Class C classification.
10.4.5 Peak Ground Acceleration
We calculated magnitude weighted surface peak ground accelerations (PGA) for the design
earthquake using the equation in NZS 1170.5 as follows.
PGA = Z.R.Ch(0)
Where: Z is the Location Hazard factor = 0.16
Ch(0) is the zero period spectral factor (Class D site, 1.12) = 1.12
R is the return factor for the earthquake return period = 1/500yr
We calculated a PGA of 0.18g for Level 2 Importance Structures, and 0.23g for Level 3 Importance
structures. We have used the above PGAs in our assessment of liquefaction across the site because
this follows the current New Zealand standard.
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We are aware that GNS have carried out a study to derive a site specific PGA for the Waikato
Expressway and that their assessment gives a lower PGA for the Ruakura area. However, results of
that study have not yet been adopted regionally and we have used the NZS1170:5 derived PGA for
our assessment.
10.5 Liquefaction
Liquefaction occurs predominantly in coarse saturated silts and fine sands and is caused by rapid
cyclic shearing and densification of the soil such that pore water pressures build up and the soil
loses strength. The potential for earthquake induced liquefaction is primarily dependent on the
earthquake magnitude, amplitude and duration characteristics, soil particle size distribution, soil
density and over-burden stress.
Liquefaction will cause significant strength loss and may cause vertical settlement and lateral
spreading after excess pore pressures dissipate. The amplitude and frequency of ground surface
motions will also affect liquefaction.
For this preliminary assessment, we have assessed the potential for liquefaction to occur during the
design earthquake and its anticipated effects using the following:
• The method by Youd et al, at the 1996 and 1998 NCEER Liquefaction Workshop and in general
accordance with the NZ Geotechnical Society ‘Geotechnical Earthquake Engineering Practice’
guidelines22.
• For fine grained soils, we assessed the potential for liquefaction using the Chinese criteria
(Kramer, 1996) described in the NCEER Liquefaction Workshop. In particular, we have
compared the Atterberg limit test results with the Chinese Criteria. We have also compared
the Plasticity Index test results to the liquefaction susceptibility criteria described in the NZ
Geotechnical Society guidelines.
• Liquefaction resistance was determined separately from the seismic CPT, CPT and borehole
SPT results. On the basis that the groundwater levels we recorded are around 1m lower than
may be expected for seasonal variation, we have assessed liquefaction using ground water
levels adjusted to 1m above than that shown on the groundwater contour plans Figures 13 to
15.
• We used the CPT liquefaction software ‘CLiq’ version.1.7.1.6 to assess the CPT results for
liquefaction potential and the risk levels for the CPT results.
• We compared the liquefaction resistance from shear wave velocities measured from the
seismic CPTs with the liquefaction resistance from CPT end cone resistance to see if the latter
may be under estimating the liquefaction resistance of the soils.
• We have also compared the results of the liquefaction assessment with the advice given in the
aforementioned NZGS guidelines.
22 NZ Geotechnical Society ‘Geotechnical earthquake engineering practice, Module 1 – Guidance for the identification, assessment and mitigation of liquefaction hazards’, dated July 2010.
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• We have also referred to Figure 5 of a paper prepared by Ishihara23 to assess the thickness of
‘non liquefiable’ soils that is needed to avoid surface damage. For the assumed PGA of 0.18g
for Level 2 Importance structures, we have considered that the uplift force due to excess pore
water pressure will not be strong enough to cause a breach in the surface layer and cause
effects such as sand boils and ground fissuring with various types of associated damage to
structures is not likely where there is a non-liquefiable surface layer of greater than 2.5m to
3m.
• Similarly, for the assumed PGA of 0.23g for Level 3 Importance structures we have assumed
that the uplift force will also not be strong enough to cause liquefaction effects where there is a
non-liquefiable surface layer of greater than 3m.
• In this preliminary assessment of liquefaction risk we have included near surface soils that
classify as ‘low risk’ for liquefaction as part of any near surface non liquefaction layer.
10.6 Stormwater Disposal
Commentary on the design (and associated constraints) of the storm water swale network and
retention ponds in relation to water runoff volumes for the proposed development is beyond the
scope of this geotechnical report.
However, in the context of this site and the proposed area of non-permeable surfaces, other
drainage options may need to be explored and these are described below.
10.6.1 Stormwater Ponds
Where the winter ground water table is shallow (<1m begl), we consider that such areas may not be
suited for stormwater drainage that relies on infiltration to the ground. However, such areas of the
site may be suited to wetland pond type stormwater storage.
Where the winter ground water table is deeper (>1m begl), we consider that such areas may be
suited for stormwater drainage options that either rely on ground infiltration or don’t. The choice
and design of options will be governed by the soils present, the soakage rates and the groundwater
levels.
The following proposed stormwater retention pond areas investigated by Cardno (investigation
location plans are presented in appendix C) have recorded groundwater at less than 1.00m below
existing ground level and this will need careful consideration in the stormwater design, particularly
where infiltration into the ground is integral to the design.
1) Stormwater Area 4, Inland Port Zone
2) Stormwater Area 5, Business Zone North of the Inland Port
3) Stormwater Area 6, AGresearch
4) Stormwater Area 7, Business Zone North of AGresearch
23 Ishihara, K. 1985. “Stability of natural deposits during earthquakes”, proceedings of the 11th International conference on soil mechanics and foundation engineering, San Francisco. PP321 to 376.
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Based on our interpretation, the Stormwater Area 2 (Business Zone south of Inland Port) appears
to have the most favourable conditions for soakage potential to the ground (groundwater table
deeper than 1m begl and a soakage rate of over 1000mm/hr into coarse grained soils).
10.6.2 Swales
The preliminary stormwater flow network and wetland sizes plan presented in Appendix A, shows a
network of swales proposed around the site. Such swales could provide some stormwater storage
potential and may also provide some soakage potential infiltrating to the ground, especially in
those areas where coarse grained soils are present at shallow depth and where groundwater levels
are at a level deeper than the base of the swale.
10.6.3 Groundwater Soakage Wells
The high permeability’s recorded the granular soils within the upper 10m indicate that these soils
may offer a potential drainage medium, especially if a significant head can be established.
However, even with high permeability rates the effect of a high groundwater level reduces this
potential for soakage to the ground.
Discharge consents will also be required for discharging to groundwater. Some form of pre-
treatment may be required for potential contamination and especially for dealing with road side
surface water drainage.
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11 Preliminary Geotechnical Considerations
11.1 Geotechnical Properties of Soils Encountered
We scoped and investigated the Stage 1 site area with the intention of formulating ‘zonation plans’
to define areas of peat/organic soils and other particular soil types may be anticipated, and zones
where generic foundation designs may be adopted.
Soils encountered across the site have been found to be both too variable laterally and horizontally
and to be generally too poor to zone the site at this stage into areas of “good ground” as originally
aimed for.
Some exploratory holes have proved the extremes of ground conditions (i.e. soft organic soils and
good foundation soils) but the variation and exploratory hole spacing has combined to make
delineation of specific areas impractical at this stage.
Based on our experience of the Hinuera soils around Hamilton and the results of this investigation,
the soil geotechnical properties on Table 6 are recommended for preliminary design. At the
detailed design stage plot/site specific assessment may allow less conservative values to be
adopted.
Soil Type 1 Soil Type 2 Soil Type 3 Soil Type 4 Soil Type 5
Soil Parameter Very soft SILT (Organic/ non
organic)
Soft to firm, SILT
Firm to stiff SILT (where encountered)
Loose silty SAND
Medium dense silty
SAND
Apparent cohesion (c′)
0 kN/m2 0 to 3kN/m
2 3 to 7kN/m
2 0kN/m
2 0kN/m
2
Angle of internal friction (Ø′)
<25° 25° 30° 30° 35°
Soil bulk unit
weight (ɤb)
12 to 16kN/m3 12 to 16kN/m
3 12 to 16kN/m
3 12 to 16kN/m
3 12 to 16kN/m
3
Undrained shear strength (Cu)
4kPa 12kPa 40kPa n/a n/a
Table 6: Generalised soil geotechnical properties across the site
In the Residential Zones primary soil types forming the near surface soils (upper 5m) are
interbedded soil types 2 to 5 locally with thin bands of type 1 soil.
In the Business Zone North of AGresearch the primary soil types forming the near surface soils
(upper 5m) are interbedded soil types 2 to 5, locally with thin bands of type 1 soil.
In the Inland Port Zone the primary soil types forming the near surface soils (upper 5m) are
interbedded soil types 2 to 5, locally with thin bands of type 1 soil.
In the Business Zone South of the Inland Port the soils generally appear to be interbedded between
soil types 2, 3 and 5, with soil type 1 encountered to unknown depth at AS137(refusal over
suspected wood fragment within organic soil).
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11.2 Residential zone – Preliminary Assessment
11.2.1 Foundations
All topsoil and very soft organic soils must be removed from below the foundation footprint.
Only two Auger Scala locations (AS104 and AS111) meet with the requirements of NZS3604:2011
for timber framed buildings for an ultimate bearing capacity requirement of not less than 300kPa.
Further investigation will be required to confirm and define the extent of these two areas of the
site.
We anticipate that specific engineering design will therefore be required for the foundations in the
majority of the residential zone.
Soil type 1 is not an acceptable foundation bearing material and undercutting of the foundations
will be needed where these are present.
We have undertaken a preliminary calculation using Verification Method B1/VM4 by the Building
Industry Authority to determine the ultimate bearing strength for 0.30, 0.45m and 0.60m wide
strip footings that are centrally and uniformly loaded founded at 0.3m, 0.50m and 1.0m depth.
In this scenario we have used the lower bound values of the soft silt soil properties for Soil Type 2
and 4 from Table 6, assuming an average soil bulk unit weight of 14kN/m2 and that groundwater
level is assumed at 0.75m below existing ground level. The calculated ultimate bearing strengths
are listed on Table 7:
Footing at 0.30m depth Footing at 0.50m depth Footing at 0.75m depth Width of Strip
Footing (m)
Soil Type 2 - Soft to firm
SILT
Soil Type 4 - Loose SAND
Soil Type 2 - Soft to firm
SILT
Soil Type 4 - Loose SAND
Soil Type 2 - Soft to firm
SILT
Soil Type 4 - Loose SAND
0.30m 70kPa 130kPa 70kPa 130kPa 155kPa 270kPa 0.45m 70kPa 130kPa 105kPa 190kPa 155kPa 270kPa 0.60m 70kPa 135kPa 110kPa 195kPa 150kPa 265kPa
Table 7: Preliminary Ultimate Bearing Strengths – Strip Footings
If at the detail design stage, the proposed structural loads cannot be accommodated by the above
ultimate bearing strengths then other options such raft or piling type foundations may need to be
adopted.
11.2.2 Foundation Settlement
We have not calculated individual settlements for the above footings as these are highly dependent
on footing size, depth and nature of the underlying soils.
We believe that provided the design bearing strength adopted is no more than a third of the soils
ultimate bearing strength then settlements should be less than 25mm. However, this needs to be
confirmed at the detailed design stage.
There is a potential for differential settlement of footings crossing different soil types. This can be
accommodated by variation in design bearing strengths or by undercutting to remove more
compressible softer soil layers.
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Alternatively reinforcement of strip footings across soil boundaries is an option to mitigate the
effects of potential differential settlement
It may be possible to develop a generic piled or raft foundation for each house / structure type in
the Stage 1 zones at the detailed design stage.
Plot specific investigations will be required to assess the bearing soil type(s) and strength that can
be assumed for each proposed structure, to confirm the need for reinforcement and any undercut
that may be required.
11.2.3 Liquefaction
Our liquefaction calculation results for the Residential Zone (from SCPT, SPT data and CPT data)
are presented in Appendix E. We have used the calculated peak ground acceleration of 0.18g in our
assessment of the Level 2 Importance Structures and 0.23g for Level 3 Importance Structures.
We have identified a number of potentially liquefiable coarse silts and fine sands with some
significant individual layer thicknesses (1m or more) present.
We have compared the potential for liquefaction to occur using the shear wave velocity measured
from the SCPT and cone resistance data obtained within the residential zone. We have found that
the potentially liquefiable layers identified between the two are similar in this instance.
Our CLiq calculation printouts are presented in Appendix F and our interpretation of the estimated
thickness of low risk near surface soils and seismically induced settlements are listed in table 8
below:
Level 2 Importance Structures (PGA = 0.18g)
Level 3 Importance Structures (PGA = 0.23g)
Exploratory Hole Thickness of surface soils at low risk of
liquefaction (m)
Estimated seismically
induced vertical settlement (mm)
Thickness of surface soils at low risk of
liquefaction (m)
Estimated seismically
induced vertical settlement (mm)
SCPT101 3.75m 34mm 3.00m 40mm CPT101 6.00m 25mm 3.75m 30mm CPT102 7.25m 27mm 6.75m 40mm
Table 8: Summary of liquefaction risk thicknesses and settlements
The thickness of soils identified at low risk of liquefaction is significant. We therefore consider that
generation of effects such as sand boils and ground fissuring with various types of associated
damage to structures with shallow foundations may be low.
The estimated differential settlement between exploratory holes is 9mm for a PGA of 0.18g and
10mm for a PGA of 0.23g. If the calculated differential settlements were spread over a similar
distance as that between exploratory holes positions, it is likely that distortion or deflexion of
structures and infrastructure would not be greater than 1/500.
Further assessment of seismically induced differential settlement will be required when plot
specific investigations are carried out for the Specific Engineering designs.
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11.2.4 Pavements
All topsoil and very soft organic soils will need to be removed from the pavement footprint.
Scala penetrometer blow counts are highly variable with depth and the CBR range is anticipated
between 0.5% and >30%. This variability reflects the interbedded and variable nature of the
subgrade soils which are predominantly fine grained sands and silts.
We generally expect that the coarser grained soils (sand and silty sand) to exhibit higher CBR’s
value than the finer grained soils (silt, sandy silt, clayey silt).
CBR’s encountered at the subgrade surface (after stripping the topsoil and cutting to the subgrade
level) will therefore be variable and will depend on the soil type being encountered at any particular
location and the depth of the soil layer.
Pavements founded on the coarser grained soils (sand and silty sand) would be likely to have a CBR
of 6% minimum. Pavements founded on the finer grained soils (silt, sandy silt, clayey silt) would
be likely to have a CBR ranging from 1% to 4% depending on its organic content, colour and
moisture content.
We recommend that the preliminary pavement design be undertaken on the basis of a design CBR
of 3%.
We note that the potential for softer areas exists and we recommend that the subgrade be
extensively tested during construction to find and undercut softer areas.
Our experience of these soils is that they are sensitive to re-working from machinery and moisture
ingress. Care will be needed to preserve the integrity of the subgrade soils. Given the risk of
rutting and deformation of the subgrade spoils from construction plant, we recommend that a
uniform construction platform be created. This may be in the form of subgrade stabilisation or the
use of geotextile or geogrid layers.
11.2.5 Floor Slabs
Undercut of compressible soils will be required for a ground bearing floor slab. Alternatively
suspended floor slabs can be adopted.
11.2.6 Other Issues and Risks
From our assessment to date, the following geotechnical and other issues pose significant risk to
the project and contingencies will need to be made to allow for these:
• Protection of exposed subgrade soils from moisture ingress and construction trafficking
• Possible undercut of sub grade due to softening of silt soils from inclement wet weather or
from re-working from trafficking machinery.
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The Preliminary Site Inspection report listed in section 1 identifies local areas of potential
contamination. Remediation of these may involve geotechnical works such as excavation, removal
and replacement with suitable material.
This will generate some localised areas with some development constraints that may require the
following:
• Avoidance
• Ground treatment
• Piling.
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11.3 Business Zone North of AGresearch
11.3.1 Foundations
All topsoil and very soft organic soils must be removed from below the foundation footprint.
None of the Auger Scala holes meet with the requirements of NZS 4229:2013 for Concrete Masonry
Buildings for ultimate bearing capacity requirement of not less than 300kPa.
We anticipate that specific engineering design will therefore be required for the foundations in this
zone.
Soil type 1 will not be an acceptable foundation bearing material and undercutting of the
foundations will be needed where these are present.
We have undertaken a preliminary calculation using Verification Method B1/VM4 by the Building
Industry Authority to determine the ultimate bearing strength for 0.30, 0.45m and 0.60m wide
strip footings that are centrally and uniformly loaded founded at 0.3m, 0.50m and 0.75m depth.
We have also determined the ultimate bearing strength for 0.50, 1.00m and 2.00m wide pad
footings that are centrally and uniformly loaded founded at 0.50m and 0.75m depth.
In this scenario we have used the lower bound values of the soft silt soil properties for Soil Type 2
and 4 from Table 6, assuming an average soil bulk unit weight of 14kN/m2 and that groundwater
level is assumed at 0.75m below existing ground level. Our calculated ultimate bearing strengths
for strip and pad footings are listed on Tables 9 and 10:
Footing at 0.30m depth Footing at 0.50m depth Footing at 0.75m depth Width of Strip
Footing (m)
Soil Type 2 - Soft to firm
SILT
Soil Type 4 - Loose SAND
Soil Type 2 - Soft to firm
SILT
Soil Type 4 - Loose SAND
Soil Type 2 - Soft to firm
SILT
Soil Type 4 - Loose SAND
0.30m 70kPa 130kPa 70kPa 130kPa 155kPa 270kPa 0.45m 70kPa 130kPa 105kPa 190kPa 155kPa 270kPa 0.60m 70kPa 135kPa 110kPa 195kPa 150kPa 265kPa
Table 9: Preliminary Ultimate Bearing Strengths for Strip Footings
Footing at 0.50m depth Footing at 0.75m depth Width of Pad Footing (m)
Soil Type 2 - Soft to firm SILT
Soil Type 4 - Loose SAND
Soil Type 2 - Soft to firm SILT
Soil Type 4 - Loose SAND
0.50m 150kPa 280kPa 220kPa 400kPa 1.00m 140kPa 265kPa 210kPa 395kPa 2.00m 140kPa 275kPa 205kPa 385kPa
Table 10: Preliminary Ultimate Bearing Strengths for Pad Footings
If at the detail design stage, the proposed structural loads cannot be accommodated by the above
ultimate bearing strengths then other option such a raft or piling type foundations may need to be
explored.
11.3.2 Foundation Settlement
We have not calculated individual settlements for the above footings as these are highly dependent
on footing size, depth and nature of the underlying soils.
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We believe that provided the design bearing strength adopted is no more than a third of the soils
ultimate bearing strength then settlements should be less than 25mm. However, this needs to be
confirmed at the detailed design stage.
There is a potential for differential settlement of footings crossing different soil types. This can be
accommodated by variation in design bearing strengths or by undercutting to remove more
compressible softer soil layers.
Alternatively reinforcement of strip footings across soil boundaries is an option to mitigate the
effects of potential differential settlement.
It may be possible to develop a generic foundation type for each structure type in the Stage 1 zones
at the detailed design stage.
Plot specific investigation will be required to assess the bearing soil type(s) and strength that can
be assumed for each proposed structure, to confirm the need for reinforcement and any undercut
that may be required.
11.3.3 Liquefaction
Our liquefaction calculation results for the Residential Zone (from SCPT, SPT data and CPT data)
are presented in Appendix G. We have used the calculated peak ground acceleration of 0.18g in our
assessment for Level 2 Importance structures and 0.23g for Level 3 Importance structures.
We have identified a number of potentially liquefiable coarse silts and fine sands with some
significant individual layer thicknesses (1m or more) present.
We have compared the potential for liquefaction to occur using the shear wave velocity measured
from the SCPT and cone resistance data obtained within the residential zone. We have found that
the potentially liquefiable layers between the two differ significantly in this instance. No
liquefaction potential is indicated for SCPT102 down to at least 13m depth, whilst in comparison a
number of the interbedded layers in the CPT are indicated to be potentially liquefiable in the upper
13m.
Our CLiq calculation printouts are presented in Appendix G and our interpretation of the estimated
thickness of low risk near surface soils and seismically induced settlements are listed in table 11
below:
Level 2 Importance Structures (PGA = 0.18g)
Level 3 Importance Structures (PGA = 0.23g)
Exploratory Hole Thickness of surface soils at low risk of
liquefaction (m)
Estimated seismically
induced vertical settlement (mm)
Thickness of surface soils at low risk of
liquefaction (m)
Estimated seismically
induced vertical settlement (mm)
SCPT102 3.25m 24mm 3.25m 24mm CPT103 3.75m 40mm 3.00m 45mm
Table 11: Summary of liquefaction risk thicknesses and settlements
The thickness of soils identified at low risk of liquefaction is significant. We therefore consider that
generation of effects such as sand boils and ground fissuring with various types of associated
damage to structures with shallow foundations may be low.
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The estimated differential settlement between exploratory holes is 16mm for a PGA of 0.18g and
21mm for a PGA of 0.23g. If the calculated differential settlements were spread over a similar
distance as that between exploratory holes positions, it is likely that distortion or deflexion of
structures and infrastructure would not be greater than 1/500.
Further assessment of seismically induced differential settlement will be required when plot
specific investigations are carried out for the Specific Engineering designs.
11.3.4 Pavements
All topsoil and very soft organic soils need to be removed from the pavement footprint.
Scala penetrometer blow counts are highly variable with depth profile and the CBR range is
anticipated between 0.5% and >30%. This variability reflects the interbedded and variable nature
of the subgrade soils which are predominantly fine grained sands and silts.
We generally expect that the coarser grained soils (sand and silty sand) to exhibit higher CBR’s
value than the finer grained soils (silt, sandy silt, clayey silt).
Subgrade CBR’s encountered at the surface (after stripping the topsoil and cutting to the subgrade
level) will therefore be variable and will depend on the soil type being encountered at any particular
location and the depth of the soil layer.
Pavements founded on the coarser grained soils (sand and silty sand) would be likely to have a CBR
of 6% minimum. Pavements founded on the finer grained soils (silt, sandy silt, clayey silt) would
be likely to have a CBR ranging from 1% to 4% depending on its organic content, colour and
moisture content.
We recommend that the preliminary pavement design be undertaken on the basis of a design CBR
of 3%.
We note that the potential for softer areas exists and we recommend that the subgrade be
extensively tested during construction to find and undercut softer areas.
Our experience of these soils is that they are sensitive to re-working from machinery and moisture
ingress. Care will be needed to preserve the integrity of the subgrade soils. Given the risk of
rutting and deformation of the subgrade spoils from construction plant, we recommend that a
uniform construction platform be created. This may be in the form of subgrade stabilisation or the
use of geotextile or geogrid layers.
11.3.5 Floor Slabs
Undercut of compressible soils will be required for a ground bearing floor slab. Alternatively
suspended floor slabs can be adopted.
11.3.6 Other Issues and Risks
From our assessment to date the following geotechnical and other issues pose significant risk to the
project and contingencies will need to be made to allow for these:
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• Protection of the subgrade soil from moisture ingress and construction trafficking
• Possible undercut of sub grade due to softening of silt soils from inclement wet weather or
from re-working from trafficking machinery.
The Preliminary Site Inspection report listed in section 1 identifies local areas of potential
contamination. Remediation of these may involve geotechnical works such as excavation, removal
and replacement with suitable material.
This will generate some localised areas with some development constraints that may require the
following:
• Avoidance
• Ground treatment
• Piling.
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11.4 Inland Port Zone
11.4.1 Settlement Beneath Fill
The only area we believe there to be fill proposed is in the Inland Port Zone.
The Inland Port area is to be raised by approximately 0.5m to 1.3m. The pavements and floor slabs
in this area are particularly sensitive to settlement and a good quality structural fill will be essential
for the long term operation of this area. We therefore consider that the site won material is not
suitable for use in this zone without significant improvement work which would carry additional
risk in to the success of the pavements in these areas.
All surface organic soils must be removed prior to placing any fill. For this preliminary assessment,
our calculated estimated consolidation settlement induced by placing 1.3m of fill in the Inland Port
Zone is listed in Table 12 below:
Exploratory Hole Estimated Total Settlement - mm
Estimated Immediate Settlement - mm
Estimated Consolidation Settlement - mm
SCPT103 95mm to 115mm 20mm to 30mm 65mm to 95mm CPT104 85mm to 100mm 20mm to 30mm 55mm to 80mm CPT105a 50mm to 65mm 30mm to 40mm 10mm to 30mm
Table 12: Estimated range of Settlement
The range of settlements indicated between the CPT locations suggest that there is a risk of
differential settlement beneath the area as a whole when considering variation in soils and the
height of fill needed.
The closely interbedded variable nature of the sand, silt and clay soils makes accurate assessment
of likely settlement rates difficult. However, we believe that the rate is likely to be relatively rapid.
Based on interpolation of the CPT and borehole data, together with the oedometer test results we
estimate that the consolidation phase should be 90% complete within 5 to 6 months of placing the
fill.
The structures and pavements proposed for the inland port area are considered to be sensitive to
differential settlement and at high risk based upon the above settlement estimates. Therefore
consolidation settlement may pose a time constraint to the development.
Pre-loading the soils is a key means of removing settlement risk. Trial fill areas are therefore
recommended to confirm the above assessment. To get the most benefit from this, this should be
carried out prior to both the detailed design stage and construction in order to allow determination
of the need for options such as pre-loading.
11.4.2 Foundations
Options for foundations include shallow footings seated wholly within the placed fill, or footings
seated in the sub-grade.
Footings within fill soils will need to be assessed once a fill source and its properties have been
determined. The following discussion is therefore tailored to footings within the natural sub-grade
soils.
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Only the Auger Scala holes AS128, AS133, AS134 meet with the requirements of NZS 4229:2013 for
Concrete Masonry Buildings for ultimate bearing capacity requirements of not less than 300kPa.
Further investigation will be required to confirm and define the extent these three areas of the site
Specific Engineering design will therefore be required for the foundations in the majority of the
Inland Port Zone.
Soil Type 1 is not an acceptable foundation bearing material and undercutting of the foundations
will be needed where these are present.
We have undertaken a preliminary calculation using Verification Method B1/VM4 by the Building
Industry Authority to determine the ultimate bearing strength for 0.30, 0.45m and 0.60m wide
strip footings that are centrally and uniformly loaded founded at 0.3m, 0.50m and 0.75m depth.
We have also determined the ultimate bearing strength for 0.50, 1.00m and 2.00m wide pad
footings that are centrally and uniformly loaded founded at 0.50m and 0.75m depth.
To aid determination of likely foundation dimensions, we have used the lower bound values of the
soft silt soil properties for Soil Type 2 and 4 from Table 6, assuming an average soil bulk unit
weight of 14kN/m2 and that groundwater level is assumed at 0.75m below existing ground level.
Our calculated ultimate bearing strengths for strip and pad footings are listed on Tables 13 and 14:
Footing at 0.30m depth Footing at 0.50m depth Footing at 0.75m depth Width of Strip
Footing (m)
Soil Type 2 - Soft to firm
SILT
Soil Type 4 - Loose SAND
Soil Type 2 - Soft to firm
SILT
Soil Type 4 - Loose SAND
Soil Type 2 - Soft to firm
SILT
Soil Type 4 - Loose SAND
0.30m 70kPa 130kPa 70kPa 130kPa 155kPa 270kPa 0.45m 70kPa 130kPa 105kPa 190kPa 155kPa 270kPa 0.60m 70kPa 135kPa 110kPa 195kPa 150kPa 265kPa
Table 13: Preliminary Ultimate Bearing Strengths for Strip Footings
Footing at 0.50m depth Footing at 0.75m depth Width of Pad Footing (m)
Soil Type 2 - Soft to firm SILT
Soil Type 4 - Loose SAND
Soil Type 2 - Soft to firm SILT
Soil Type 4 - Loose SAND
0.50m 150kPa 280kPa 220kPa 400kPa 1.00m 140kPa 265kPa 210kPa 395kPa 2.00m 140kPa 275kPa 205kPa 385kPa
Table 14: Preliminary Ultimate Bearing Strengths for Pad Footings
If at the detail design stage, the proposed structural loads cannot be accommodated by the above
bearing strengths then other option such a raft or piling type foundations can be explored.
11.4.1 Foundation Settlement
We have not calculated individual settlements for the above footings as these are highly dependent
on footing size, depth and nature of the underlying soils.
We believe that provided the design bearing strength adopted is no more than a third of the soils
ultimate bearing strength then settlements should be less than 25mm. However, this needs to be
confirmed at the detailed design stage.
44
Ruakura Development: Stage 1 Geotechnical Investigation. Interpretive Report
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There is a potential for differential settlement of footings crossing different soil types. This can be
accommodated by variation in design bearing strengths or by undercutting to remove more
compressible softer soil layers.
Reinforcement of footings across soil boundaries is an option to mitigate the effects of potential
differential settlement.
It may be possible to develop a generic foundation design for each structure type in the Stage 1
zones at the detailed design stage.
Plot specific investigations will be required to assess the bearing soil type(s) and strength that can
be assumed for each proposed structure, to confirm the need for reinforcement and to confirm any
undercut that may be required.
11.4.2 Liquefaction
Our liquefaction calculation results for the Inland Port Zone (from SCPT, SPT data and CPT data)
are presented in Appendix H. We have used the calculated peak ground acceleration of 0.18gfor
Level 2 Importance structures and 0.23g for Level 3 Importance structures.
We have identified a number of potentially liquefiable coarse silts and fine sands with some
significant individual layer thicknesses recorded.
We have compared the potential for liquefaction to occur using the shear wave velocity measured
from the SCPT and cone resistance data obtained within the residential zone. We have found that
the potentially liquefiable layers generally identified between the two are similar with some
variance.
Our CLiq calculation printouts are presented in Appendix H and our interpretation of the
estimated thickness of low risk near surface soils and seismically induced settlements are listed in
table 15 below:
Level 2 Importance Structures (PGA = 0.18g)
Level 3 Importance Structures (PGA = 0.23g)
Exploratory Hole Thickness of surface soils at low risk of
liquefaction (m)
Estimated seismically
induced vertical settlement (mm)
Thickness of surface soils at low risk of
liquefaction (m)
Estimated seismically
induced vertical settlement (mm)
SCPT103 >20m 8mm 7.00m 10mm CPT104 >20m 20mm 15m 24mm CPT105 11.25m 22mm 7.75m 26mm
Table 15: Summary of liquefaction risk thicknesses and settlements
The thickness of soils identified at low risk of liquefaction is significant. We therefore consider that
generation of effects such as sand boils and ground fissuring with various types of associated
damage to structures with shallow foundations may be low.
The estimated differential settlement between exploratory holes is 14mm for a PGA of 0.18g and
16mm for a PGA of 0.23g. If the calculated differential settlements were spread over a similar
distance as that between exploratory holes positions, it is likely that distortion or deflexion of
structures and infrastructure would not be greater than 1/500.
45
Ruakura Development: Stage 1 Geotechnical Investigation. Interpretive Report
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Further assessment of seismically induced differential settlement will be required when plot
specific investigations are carried out for the Specific Engineering designs.
11.4.1 Pavements
A separate report has been prepared to cover the pavement design considerations in this area.
All topsoil and very soft organic soils will be required to be removed from the pavement footprint.
Scala penetrometer blow counts are highly variable with depth profile and the CBR range is
anticipated between 0.5% and >30%. This variability reflects the interbedded and variable nature
of the subgrade soils which are predominantly fine grained sands and silts.
We generally expect that the coarser grained soils (sand and silty sand) to exhibit higher CBR’s
value than the finer grained soils (silt, sandy silt, clayey silt).
CBR’s encountered at the subgrade surface (after stripping the topsoil and cutting to the subgrade
level) will therefore be variable and will depend on the soil type being encountered at any particular
location and the depth of the soil layer.
Pavements founded on the coarser grained soils (sand and silty sand) would be likely to have a CBR
of 6% minimum. Pavements founded on the finer grained soils (silt, sandy silt, clayey silt) would
be likely to have a CBR ranging from 1% to 4% depending on its organic content, colour and
moisture content.
We recommend that the preliminary pavement design be undertaken on the basis of a design CBR
of 3%.
We note that the potential for softer areas exists and we recommend that the subgrade be
extensively tested during construction to find and undercut softer areas.
Our experience of these soils is that they are sensitive to re-working from machinery and moisture
ingress. Care will be needed to preserve the integrity of the subgrade soils. Given the risk of
rutting and deformation of the subgrade spoils from construction plant, we recommend that a
uniform construction platform be created. This may be in the form of subgrade stabilisation or the
use of geotextile or geogrid layers.
11.4.2 Floor Slabs
Undercut of compressible soils need to be carried out for a ground bearing floor slab. Alternatively
suspended floor slabs can be adopted.
11.4.3 Other Issues and Risks
From our assessment to date the following geotechnical and other issues pose significant risk to the
project and contingencies will need to be made to allow for these:
• Fill source determination, laboratory testing and trial fill areas
• Protection of the subgrade from moisture ingress and construction trafficking
46
Ruakura Development: Stage 1 Geotechnical Investigation. Interpretive Report
| Opus International Consultants Ltd
• Possible undercut of sub grade due to softening of silt soils from inclement wet weather or
from re-working from trafficking machinery.
The Preliminary Site Inspection report listed in section 1 identifies local areas of potential
contamination. Remediation of these may involve geotechnical works such as excavation, removal
and replacement with suitable material.
This will generate some localised areas with some development constraints that may require the
following:
• Avoidance
• Ground treatment
• Piling.
47
Ruakura Development: Stage 1 Geotechnical Investigation. Interpretive Report
| Opus International Consultants Ltd
11.5 Business Zone South of Inland Port
11.5.1 Foundations
All topsoil and very soft organic soils must be removed from below the foundation footprint.
None of the Auger Scala holes meet with the requirements of NZS 4229:2013 for Concrete Masonry
Buildings for ultimate bearing capacity requirement of not less than 300kPa.
We therefore anticipate that specific engineering design will therefore be required for the
foundations in this zone.
Soil Type 1 is not an acceptable foundation bearing material and undercutting of the foundations
will be needed where these are present.
We have undertaken a preliminary calculation using Verification Method B1/VM4 by the Building
Industry Authority to determine the ultimate bearing strength for 0.30, 0.45m and 0.60m wide
strip footings that are centrally and uniformly loaded founded at 0.3m, 0.50m and 0.75m depth.
We have also determined the ultimate bearing strength for 0.50, 1.00m and 2.00m wide pad
footings that are centrally and uniformly loaded founded at 0.50m and 0.75m depth.
In this scenario we have used the lower bound values of the soft silt soil properties for Soil Type 2
and 5 from Table 6, assuming an average soil bulk unit weight of 14kN/m2 and that groundwater
level is assumed at 0.75m below existing ground level. Our calculated ultimate bearing strengths
for strip and pad footings are listed on Tables 16 and 17:
Footing at 0.30m depth Footing at 0.50m depth Footing at 0.75m depth Width of Strip Footing (m)
Soil Type 2 - Soft to firm SILT
Soil Type 5 – Medium Dense SAND
Soil Type 2 - Soft to firm SILT
Soil Type 5 - Medium Dense SAND
Soil Type 2 - Soft to firm SILT
Soil Type 5 - Medium Dense SAND
0.30m 70kPa 250kPa 70kPa 255kPa 155kPa 480kPa 0.45m 70kPa 255kPa 105kPa 350kPa 155kPa 480kPa 0.60m 70kPa 260kPa 110kPa 365kPa 150kPa 485kPa
Table 16: Preliminary Ultimate Bearing Strengths for Strip Footings
Footing at 0.50m depth Footing at 0.75m depth Width of Pad Footing (m)
Soil Type 2 - Soft to firm SILT
Soil Type 5 – Medium Dense SAND
Soil Type 2 - Soft to firm SILT
Soil Type 5 – Medium Dense SAND
0.50m 150kPa 540kPa 220kPa 770kPa 1.00m 140kPa 520kPa 210kPa 765kPa 2.00m 140kPa 550kPa 205kPa 765kPa
Table 17: Preliminary Ultimate Bearing Strengths for Pad Footings
If at the detail design stage, the proposed structural loads cannot be accommodated by the above
bearing strengths then other option such a raft or piling type foundations can be explored.
11.5.1 Foundation Settlement
We have not calculated individual settlements for the above footings as these are highly dependent
on footing size, depth and nature of the underlying soils.
48
Ruakura Development: Stage 1 Geotechnical Investigation. Interpretive Report
| Opus International Consultants Ltd
We believe that provided the design bearing strength adopted is no more than a third of the soils
ultimate bearing strength then settlements should be less than 25mm. However, this needs to be
confirmed at the detailed design stage.
There is a potential for differential settlement of footings crossing different soil types. This can be
accommodated by variation in design bearing strengths or by undercutting to remove more
compressible softer soil layers.
There is a potential for differential settlement on footings crossing different soil types. This can be
accommodated by variation in design bearing strengths or by undercutting to remove more
compressible softer soil layers.
Reinforcement of footings across soil boundaries is an option to mitigate the effects of potential
differential settlement.
It may be possible to develop a generic foundation design for each structure type in the Stage 1
zones at the detailed design stage.
Plot specific investigations will be required to assess the bearing soil type(s) and strength that can
be assumed for each proposed structure, to confirm the need for reinforcement and to confirm any
undercut that may be required. This work will also be required to delineate the extent of soft
organic soils encountered in AS137.
11.5.2 Liquefaction
Our liquefaction calculation results for the boreholes are presented in Appendix I. We have
assumed a calculated peak ground acceleration of 0.18g for Level 2 Importance structures.
We have assessed the potential liquefaction risk from SPT data and have identified that there is a
risk of liquefaction.
The results are broadly similar to those seen elsewhere on the site. However due to the non-
continuous nature of the SPT tests the test results do not give us as clear an indication of the
distribution of liquefiable soils as the CPTs. For preliminary design purposes we believe that it is
reasonable to assume that the near surface soils are at low risk of liquefaction. The SPT data
suggests that this upper layer may be approximately 4m thick. We therefore consider that
generation of effects such as sand boils and ground fissuring with various types of associated
damage to structures may be low.
We recommend that Seismic CPTs and CPTs are carried out in this Business Zone in order to
further assess / confirm the liquefaction potential and associated settlements.
11.5.3 Pavements
All topsoil and very soft organic soils will be required to be removed from the pavement footprint.
Scala penetrometer blow counts are highly variable with depth and the CBR range is anticipated
between 0.5% and >30%. This variability reflects the interbedded and variable nature of the
subgrade soils which are predominantly fine grained sands and silts.
49
Ruakura Development: Stage 1 Geotechnical Investigation. Interpretive Report
| Opus International Consultants Ltd
We generally expect that the coarser grained soils (sand and silty sand) to exhibit higher CBR’s
value than the finer grained soils (silt, Sandy silt, clayey silt).
CBR’s encountered at the subgrade surface (after stripping the topsoil and cutting to the subgrade
level) will therefore be variable and will depend on the soil type being encountered at any particular
location and the depth of the soil layer.
Pavements founded on the coarser grained soils (sand and silty sand) would be likely to have a CBR
of 6% minimum. Pavements founded on the finer grained soils (silt, Sandy silt, clayey silt) would
be likely to have a CBR ranging from 1% to 4% depending on its organic content, colour and
moisture content.
We recommend that the preliminary pavement design be undertaken on the basis of a design CBR
of 3%.
We note that the potential for softer areas exists and we recommend that the subgrade be
extensively tested during construction to find and undercut softer areas.
Our experience of these soils is that they are sensitive to re-working from machinery and moisture
ingress. Care will be needed to preserve the integrity of the subgrade soils. Given the risk of
rutting and deformation of the subgrade spoils from construction plant, we recommend that a
uniform construction platform be created. This may be in the form of subgrade stabilisation or the
use of geotextile or geogrid layers.
11.5.4 Floor Slabs
Undercut of compressible soils will be needed for ground bearing floor slabs. Alternatively
suspended floor slabs can be adopted.
11.5.5 Other Issues and Risks
From our assessment to date, the following geotechnical and other issues pose significant risk to
the project and contingencies will need to be made to allow for these:
• Protection of the subgrade from moisture ingress and construction trafficking
• Possible undercut of sub grade due to softening of silt soils from inclement wet weather or
from re-working from trafficking machinery.
The Preliminary Site Inspection report listed in section 1 identifies local areas of potential
contamination. Remediation of these may involve geotechnical works such as excavation, removal
and replacement with suitable material.
This will generate some localised areas with some development constraints that may require the
following:
• Avoidance
• Ground treatment
• Piling.
50
Ruakura Development: Stage 1 Geotechnical Investigation. Interpretive Report
| Opus International Consultants Ltd
12 Recommendations
12.1 Stage 1 Investigation Areas
We recommend the following prior to the detailed design and construction of the Stage 1
investigation zones:
1) Continue groundwater monitoring through winter period.
2) Determine the potential source of fill and carry out laboratory testing to determine the
compaction and foundation properties of this material.
3) Carry out further investigation of those locations where:
a) Soft, compressible and organic rich soils have been proved at the ground surface.
b) Where bearing strength areas in excess of 300kPa have been proved.
The above is recommended to determine the lateral extent of these areas.
4) Carry out CPT investigation in the Business Zone South of the Inland Port and further seismic
CPTs across the whole site to further assess / confirm the liquefaction potential.
5) Seek permission from HCC / NZTA to use the GNS site specific PGA for the Waikato
Expressway.
6) Carry out a trial fill with monitoring within the Inland Port Zone to better determine the
amount of consolidation settlement and any differential settlement issues.
12.2 Balance of Ruakura Development
We recommend the following for the balance of the Ruakura Development
a) Geotechnical Investigation of those zones not already investigated to date;
b) Follow up investigations as necessary which may be broadly similar to the Stage 1 investigation
areas and will be depend on the development proposals.
Note: Image sourced from Google Earth
Tainui Group Holdings Ltd FIGURE 1: SITE LOCATION PLAN
7/05/2013 2-32113.00 Ruakura Development Stage 1: Geotechnical Investigation Factual Report
Drawing Not to Scale
Key Ruakura Development Stage 1
Ruakura Development Future Stages
Residential Zones
Inland Port Zone Business Zone North of Agresearch
Business Zone South of Agresearch
AS101
AS102
AS103
AS104
AS105
AS106
AS107
AS108
AS109
AS110
AS111
AS112
AS113
AS114
AS115
AS116
AS117
AS118
AS119
AS120
BH101
CPT101
CPT102
SCPT101
TP101
TP102
TP103
S
e
c
tio
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1
S
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2
S
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3
500
1:5000
0 10050 150 350200 250 300 400 450
m
@ A1
@ A31:10000
Approved Revision DateRevision Amendment
LEGEND
RESIDENTIAL ZONES
BOREHOLE
CPT
SEISMIC CPT
AUGER SCALA
TEST PIT
GEOLOGICAL CROSS SECTIONS
(ARROW DENOTES DIRECTION OF
CROSS SECTION VIEW)
200
100
5010
0mm
300
mm
ScaleProject No. Drawing No. Sheet. No.
Project
Sheet
Revision
Original Sheet Size A1 [841x594] Plot Date 26 Jun 2013 @ 9:00 a.m. Path G:\232100\32113_00 Ruakura TGH\Drawings\CAD\Interpretive Report\2_1826_5_5204_FIG_2-4.dwg FIG.2
Drawn Approved Revision DateDesigned
Hamilton Office Private Bag 3057Hamilton 3240New Zealand+64 7 838 9344
TAINUI GROUP HOLDINGS LTDSTAGE 1 GEOTECHNICAL INVESTIGATIONSRUAKURA DEVELOPMENT
FIGURE 2: EXPLORATORY HOLE LOCATION PLANRESIDENTIAL ZONES
2/1826/5/5204 FIG.2 R1232113.00 1:5000 [A1] 1:10000 [A3]
G.M.B. 22May13
Hamilton Ring Road
Tramway Road
Greenhill R
oad
Pow
ells R
oad
Section 1
R
u
a
k
u
r
a
R
o
a
d
AS121
AS122
AS123
AS124
AS125
AS126
BH102
BH103
CPT103
SCPT102
TP105
TP106
TP107
TP108
TP104
Section 5
Section 4
Approved Revision DateRevision Amendment
LEGEND
BUSINESS ZONE NORTH OF
AGRESEARCH
BOREHOLE
CPT
SEISMIC CPT
AUGER SCALA
TEST PIT
GEOLOGICAL CROSS SECTIONS
(ARROW DENOTES DIRECTION
OF CROSS SECTION VIEW)
500
1:5000
0 10050 150 350200 250 300 400 450
m
@ A1
@ A31:10000
200
100
5010
0mm
300
mm
ScaleProject No. Drawing No. Sheet. No.
Project
Sheet
Revision
Original Sheet Size A1 [841x594] Plot Date 26 Jun 2013 @ 9:02 a.m. Path G:\232100\32113_00 Ruakura TGH\Drawings\CAD\Interpretive Report\2_1826_5_5204_FIG_2-4.dwg FIG.3
Drawn Approved Revision DateDesigned
Hamilton Office Private Bag 3057Hamilton 3240New Zealand+64 7 838 9344
TAINUI GROUP HOLDINGS LTDSTAGE 1 GEOTECHNICAL INVESTIGATIONSRUAKURA DEVELOPMENT
FIGURE 3: EXPLORATORY HOLE LOCATION PLANBUSINESS ZONE NORTH OF AGRESEARCH
2/1826/5/5204 FIG.3 R1232113.00 1:5000 [A1] 1:10000 [A3]
G.M.B. 22May13
Hamilton Ring Road
Tramway Road
Pow
ells R
oad
R
u
a
k
u
ra
R
o
a
d
AGRESEARCH
INNOVATION PARK
Section 4
S
ilv
e
r
d
a
le
R
o
a
d
R
u
a
k
u
r
a
R
o
a
d
AS127
AS128
AS130
AS131
AS132
AS133
AS134
AS135
AS136
AS137
AS138
AS139
AS140
AS141
AS142
AS143
AS144
BH104
BH105
BH106
BH107
BH108 DEEP
BH108 SHALLOW
BH109
BH110
BH111
BH112
CPT104
CPT105
SCPT103
TP109
TP110
TP111
TP112
TP113
TP114
TP115
TP116
S
e
c
t
i
o
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6
S
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c
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8
S
e
ctio
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7
Approved Revision DateRevision Amendment
LEGEND
INLAND PORT ZONE
BUSINESS ZONE SOUTH OF
INLAND PORT
BOREHOLE
CPT
SEISMIC CPT
AUGER SCALA
TEST PIT
GEOLOGICAL CROSS SECTIONS
(ARROW DENOTES DIRECTION
OF CROSS SECTION VIEW)
500
1:5000
0 10050 150 350200 250 300 400 450
m
@ A1
@ A31:10000
200
100
5010
0mm
300
mm
ScaleProject No. Drawing No. Sheet. No.
Project
Sheet
Revision
Original Sheet Size A1 [841x594] Plot Date 26 Jun 2013 @ 9:03 a.m. Path G:\232100\32113_00 Ruakura TGH\Drawings\CAD\Interpretive Report\2_1826_5_5204_FIG_2-4.dwg FIG.4
Drawn Approved Revision DateDesigned
Hamilton Office Private Bag 3057Hamilton 3240New Zealand+64 7 838 9344
TAINUI GROUP HOLDINGS LTDSTAGE 1 GEOTECHNICAL INVESTIGATIONSRUAKURA DEVELOPMENT
FIGURE 4: EXPLORATORY HOLE LOCATION PLANINLAND PORT ZONE AND BUSINESS ZONE TO SOUTH
2/1826/5/5204 FIG.4 R1232113.00 1:5000 [A1] 1:10000 [A3]
G.M.B. 22May13
AGRESEARCH
Section 6
30
31
32
33
34
35
36
37
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01002003004005006007008009001,0001,1001,2001,30030
31
32
33
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39
40
01002003004005006007008009001,0001,1001,2001,300
LITHOLOGY GRAPHICS (Colours schematic only)
Horizontal 1:3862.0689910069Vertical 1:50.00000033
Peat/TopsoilSandSilt-Sand
Ele
va
tio
n (
me
tre
s)
Distance Along Baseline (metres)
Silt Gravel
Project Number: 2-32113.00
Clay
Topsoil BSI Silty Sand BSI Sandy Silt BSI Sand BSI Peat BSI Silt
Clay-Silt
North
Ruakura Development Stage 1 Investigations
South
Peaty Silt
Scale 1:50 (V)(BSI = British Standard Institute graphics as adopted by NZGS)
Tainui Group Holdings Ltd
FIGURE 5 - Geological Cross-Section 1:Residential Zone
A3
AS
CP
T B
H F
EN
CE
RU
AK
UR
A
2-3
21
13
.00
.GP
J
CO
MB
O_
TE
M_
MA
R1
3.G
DT
2
8/5
/13
-- A
S1
01
ScalaBlows/100mm
-- A
S1
05
ScalaBlows/100mm
-- A
S1
09
ScalaBlows/100mm
-- A
S1
13
ScalaBlows/100mm
-- B
H.1
01
SPTN
ConeResistance
MPa
-- C
PT
.10
1
0 5 10 15 20
ConeResistance
MPa
-- C
PT
.10
2
0 5 10 15 20
ConeResistance
MPa
-- S
CP
T.1
01
0 5 10 15 20
-- T
P1
01
ScalaBlows/100mm
0 10 20
0 10 20
0 10 20
0 10 20
0 10 20
30
31
32
33
34
35
36
37
38
39
40
0 50 100 150 200 250 300 350 400 45030
31
32
33
34
35
36
37
38
39
40
0 50 100 150 200 250 300 350 400 450
LITHOLOGY GRAPHICS (Colours schematic only)
Horizontal 1:1241.37931853793Vertical 1:50.00000033
Peat/TopsoilSandSilt-Sand
Ele
va
tio
n (
me
tre
s)
Distance Along Baseline (metres)
Silt Gravel
Project Number: 2-32113.00
Clay
BSI Sandy Silt BSI SiltBSI ClayeySilt
BSI Sand Topsoil BSI Silty Sand
Clay-Silt
West
Ruakura Development Stage 1 Investigations
East
Peaty Silt
Scale 1:50 (V)(BSI = British Standard Institute graphics as adopted by NZGS)
Tainui Group Holdings Ltd
FIGURE 6 - Geological Cross-Section 2:Residential Zone
A3
AS
CP
T B
H F
EN
CE
RU
AK
UR
A
2-3
21
13
.00
.GP
J
CO
MB
O_
TE
M_
MA
R1
3.G
DT
2
8/5
/13
-- A
S1
03
ScalaBlows/100mm
-- A
S1
04
ScalaBlows/100mm
-- B
H.1
01
SPTN
ConeResistance
MPa
-- S
CP
T.1
01
0 5 10 15 20
-- T
P1
01
ScalaBlows/100mm
0 10 20
0 10 200 10 20
35
36
37
38
39
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41
42
43
44
45
0 50 100 150 200 250 300 350 40035
36
37
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39
40
41
42
43
44
45
0 50 100 150 200 250 300 350 400
LITHOLOGY GRAPHICS (Colours schematic only)
Horizontal 1:1103.44828314483Vertical 1:50.00000033
Peat/TopsoilSandSilt-Sand
Ele
va
tio
n (
me
tre
s)
Distance Along Baseline (metres)
Silt Gravel
Project Number: 2-32113.00
Clay
BSI Silty Sand BSI Sandy Silt BSI SiltBSI ClayeySilt
BSI Silty Clay
Clay-Silt
West
Ruakura Development Stage 1 Investigations
East
Peaty Silt
Scale 1:50 (V)(BSI = British Standard Institute graphics as adopted by NZGS)
Tainui Group Holdings Ltd
FIGURE 7 - Geological Cross-Section 3:Residential Zone
A3
AS
CP
T B
H F
EN
CE
RU
AK
UR
A
2-3
21
13
.00
.GP
J
CO
MB
O_
TE
M_
MA
R1
3.G
DT
2
8/5
/13
-- A
S1
10
ScalaBlows/100mm
-- A
S1
11
ScalaBlows/100mm
ConeResistance
MPa
-- C
PT
.10
2
0 5 10 15 20
0 10 20
0 10 20
32
33
34
35
36
37
38
39
40
41
42
05010015020025030035040045032
33
34
35
36
37
38
39
40
41
42
050100150200250300350400450
LITHOLOGY GRAPHICS (Colours schematic only)
Horizontal 1:1351.72414685241Vertical 1:50.00000033
Peat/TopsoilSandSilt-Sand
Ele
va
tio
n (
me
tre
s)
Distance Along Baseline (metres)
Silt Gravel
Project Number: 2-32113.00
Clay
BSI Sandy Silt BSI Silt BSI Sand Topsoil BSI Silty SandBSI Silt withPeat
Clay-Silt
North
Ruakura Development Stage 1 Investigations
South
Peaty Silt
Scale 1:50 (V)(BSI = British Standard Institute graphics as adopted by NZGS)
Tainui Group Holdings Ltd
FIGURE 8 - Geological Cross-Section 4:Business Zone North of AgResearch
A3
AS
CP
T B
H F
EN
CE
RU
AK
UR
A
2-3
21
13
.00
.GP
J
CO
MB
O_
TE
M_
MA
R1
3.G
DT
2
8/5
/13
-- A
S1
26
ScalaBlows/100mm
-- B
H.1
02
SPTN Cone
ResistanceMPa
-- C
PT
.10
3
0 5 10 15 20
-- T
P1
04
ScalaBlows/100mm
-- T
P1
07
ScalaBlows/100mm
0 10 200 10 20
0 10 20
32
33
34
35
36
37
38
39
40
41
42
0 100 200 300 400 500 600 700 800 90032
33
34
35
36
37
38
39
40
41
42
0 100 200 300 400 500 600 700 800 900
LITHOLOGY GRAPHICS (Colours schematic only)
Horizontal 1:2482.75863707586Vertical 1:50.00000033
Peat/TopsoilSandSilt-Sand
Ele
va
tio
n (
me
tre
s)
Distance Along Baseline (metres)
Silt Gravel
Project Number: 2-32113.00
Clay
BSI Sandy Silt BSI Silt BSI Sand Topsoil BSI Silty Sand BSI PeatBSI GravellySand
Clay-Silt
West
Ruakura Development Stage 1 Investigations
East
Peaty Silt
Scale 1:50 (V)(BSI = British Standard Institute graphics as adopted by NZGS)
Tainui Group Holdings Ltd
FIGURE 9 - Geological Cross-Section 5:Business Zone North of AgResearch
A3
AS
CP
T B
H F
EN
CE
RU
AK
UR
A
2-3
21
13
.00
.GP
J
CO
MB
O_
TE
M_
MA
R1
3.G
DT
2
8/5
/13
-- A
S1
21
ScalaBlows/100mm
-- A
S1
22
ScalaBlows/100mm--
AS
12
3
ScalaBlows/100mm
-- A
S1
25
ScalaBlows/100mm
-- B
H.1
02
SPTN Cone
ResistanceMPa
-- C
PT
.10
3
0 5 10 15 20
ConeResistance
MPa
-- S
CP
T.1
02
0 5 10 15 20
0 10 20
0 10 20
0 10 20
0 10 20
34
35
36
37
38
39
40
41
42
43
44
0 100 200 300 400 500 600 700 800 900 1,000 1,100 1,200 1,30034
35
36
37
38
39
40
41
42
43
44
0 100 200 300 400 500 600 700 800 900 1,000 1,100 1,200 1,300
19
/04
/20
13
8/0
4/2
01
3
LITHOLOGY GRAPHICS (Colours schematic only)
Horizontal 1:3586.20692022069Vertical 1:50.00000033
Peat/TopsoilSandSilt-Sand
Ele
va
tio
n (
me
tre
s)
Distance Along Baseline (metres)
Silt Gravel
Project Number: 2-32113.00
Clay
BSI Silt BSI Sand Topsoil BSI Sandy Silt BSI Silty SandBSI GravellySand
BSI SandyGravel
BSI Gravel
Clay-Silt
North
Ruakura Development Stage 1 Investigations
South
Peaty Silt
Scale 1:50 (V)(BSI = British Standard Institute graphics as adopted by NZGS)
Tainui Group Holdings Ltd
FIGURE 10 - Geological Cross-Section 6:Inland Port Zone and Business Zone to
South
A3
AS
CP
T B
H F
EN
CE
RU
AK
UR
A
2-3
21
13
.00
.GP
J
CO
MB
O_
TE
M_
MA
R1
3.G
DT
2
8/5
/13
-- A
S1
35
ScalaBlows/100mm
-- A
S1
39
ScalaBlows/100mm
-- A
S1
44
ScalaBlows/100mm
-- B
H.1
09
SPTN
-- B
H.1
10
SPTN
-- T
P1
09
ScalaBlows/100mm
-- T
P1
14
ScalaBlows/100mm
-- T
P1
15
ScalaBlows/100mm
0 10 20
0 10 20
0 10 200 10 20
0 10 200 10 20
34
35
36
37
38
39
40
41
42
43
44
0 100 200 300 400 500 600 700 800 900 1,000 1,100 1,20034
35
36
37
38
39
40
41
42
43
44
0 100 200 300 400 500 600 700 800 900 1,000 1,100 1,200
LITHOLOGY GRAPHICS (Colours schematic only)
Horizontal 1:3310.34484943448Vertical 1:50.00000033
Peat/TopsoilSandSilt-Sand
Ele
va
tio
n (
me
tre
s)
Distance Along Baseline (metres)
Silt Gravel
Project Number: 2-32113.00
Clay
BSI Silt BSI Sandy Silt BSI Sand Topsoil BSI Silty SandBSI GravellySand
BSI ClayeySilt
BSI Silt withPeat
Clay-Silt
West
Ruakura Development Stage 1 Investigations
East
Peaty Silt
Scale 1:50 (V)(BSI = British Standard Institute graphics as adopted by NZGS)
Tainui Group Holdings Ltd
FIGURE 11 - Geological Cross-Section 7:Inland Port Zone
A3
AS
CP
T B
H F
EN
CE
RU
AK
UR
A
2-3
21
13
.00
.GP
J
CO
MB
O_
TE
M_
MA
R1
3.G
DT
2
8/5
/13
-- A
S1
27
ScalaBlows/100mm
-- A
S1
28
ScalaBlows/100mm
-- B
H.1
04
SPTN
-- B
H.1
05
SPTN
-- B
H.1
06
SPTN
ConeResistance
MPa
-- C
PT
.10
4
0 5 10 15 20
ConeResistance
MPa
-- S
CP
T.1
03
0 5 10 15 20
-- T
P1
09
ScalaBlows/100mm --
TP
11
0
ScalaBlows/100mm
0 10 20
0 10 20
0 10 20
0 10 20
34
35
36
37
38
39
40
41
42
43
44
0 100 200 300 400 500 600 700 800 900 1,00034
35
36
37
38
39
40
41
42
43
44
0 100 200 300 400 500 600 700 800 900 1,000
LITHOLOGY GRAPHICS (Colours schematic only)
Horizontal 1:2758.62070786207Vertical 1:50.00000033
Peat/TopsoilSandSilt-Sand
Ele
va
tio
n (
me
tre
s)
Distance Along Baseline (metres)
Silt Gravel
Project Number: 2-32113.00
Clay
BSI Silt BSI Sandy Silt BSI SandBSI GravellySand
BSI Silty Sand Topsoil
Clay-Silt
West
Ruakura Development Stage 1 Investigations
East
Peaty Silt
Scale 1:50 (V)(BSI = British Standard Institute graphics as adopted by NZGS)
Tainui Group Holdings Ltd
FIGURE 12 - Geological Cross-Section 8:Business Zone South of Inland Port
A3
AS
CP
T B
H F
EN
CE
RU
AK
UR
A
2-3
21
13
.00
.GP
J
CO
MB
O_
TE
M_
MA
R1
3.G
DT
2
8/5
/13
-- A
S1
40
ScalaBlows/100mm
-- A
S1
41
ScalaBlows/100mm
-- A
S1
42
ScalaBlows/100mm
-- B
H.1
11
SPTN --
TP
11
5
ScalaBlows/100mm
-- T
P1
16
ScalaBlows/100mm
0 10 20
0 10 20
0 10 20
0 10 20
0 10 20
AS101
AS102
AS103
AS104
AS105
AS106
AS107
AS108
AS109
AS110
AS111
AS112
AS113
AS114
AS115
AS116
AS117
AS118
AS119
AS120
BH101
CPT101
CPT102
SCPT101
TP101
TP102
TP103
3
6
3
5
3
4
3
4
3
5
3
6
3
6
3
7
3
8
500
1:5000
0 10050 150 350200 250 300 400 450
m
@ A1
@ A31:10000
Approved Revision DateRevision Amendment
LEGEND
RESIDENTIAL STAGE 1
BOREHOLE
CPT
SEISMIC CPT
AUGER SCALA
TEST PIT
APPROXIMATE GROUNDWATER
CONTOUR LEVEL FOR SHALLOW
PIEZOMETERS [BASED ON 3/5/13
MONITORING RESULTS
200
100
5010
0mm
300
mm
ScaleProject No. Drawing No. Sheet. No.
Project
Sheet
Revision
Original Sheet Size A1 [841x594] Plot Date 26 Jun 2013 @ 9:04 a.m. Path G:\232100\32113_00 Ruakura TGH\Drawings\CAD\Interpretive Report\2_1826_5_5204_FIG_13-15.dwg FIG.13
Drawn Approved Revision DateDesigned
Hamilton Office Private Bag 3057Hamilton 3240New Zealand+64 7 838 9344
TAINUI GROUP HOLDINGS LTDSTAGE 1 GEOTECHNICAL INVESTIGATIONSRUAKURA DEVELOPMENT
FIGURE 13: GROUNDWATER CONTOURPLAN OF RESIDENTIAL ZONES
2/1826/5/5204 FIG.13 R1232113.00 1:5000 [A1] 1:10000 [A3]
G.M.B. 22May13
Hamilton Ring Road
Tramway Road
Greenhill R
oad
Pow
ells R
oad
38
38
R
u
a
k
u
r
a
R
o
a
d
AS121
AS122
AS123
AS124
AS125
AS126
BH102
BH103
CPT103
SCPT102
TP105
TP106
TP107
TP108
TP104
3
6
3
6
3
7
3
8
3
8
3
7
3
6
3
9
3
8
3
8
Approved Revision DateRevision Amendment
LEGEND
BUSINESS ZONE STAGE 1
BOREHOLE
CPT
SEISMIC CPT
AUGER SCALA
TEST PIT
APPROXIMATE GROUNDWATER
CONTOUR LEVEL FOR SHALLOW
PIEZOMETERS [BASED ON 3/5/13
MONITORING RESULTS
500
1:5000
0 10050 150 350200 250 300 400 450
m
@ A1
@ A31:10000
200
100
5010
0mm
300
mm
ScaleProject No. Drawing No. Sheet. No.
Project
Sheet
Revision
Original Sheet Size A1 [841x594] Plot Date 26 Jun 2013 @ 9:04 a.m. Path G:\232100\32113_00 Ruakura TGH\Drawings\CAD\Interpretive Report\2_1826_5_5204_FIG_13-15.dwg FIG.14
Drawn Approved Revision DateDesigned
Hamilton Office Private Bag 3057Hamilton 3240New Zealand+64 7 838 9344
TAINUI GROUP HOLDINGS LTDSTAGE 1 GEOTECHNICAL INVESTIGATIONSRUAKURA DEVELOPMENT
FIGURE 14: APROXIMATE GROUNDWATER CONTOURPLAN OF BUSINESS ZONE NORTH OF AGRESEARCH
2/1826/5/5204 FIG.14 R1232113.00 1:5000 [A1] 1:10000 [A3]
G.M.B. 22May13
Hamilton Ring Road
Tramway Road
Pow
ells R
oad
R
u
a
k
u
ra
R
o
a
d
AGRESEARCH
INNOVATION PARK
38
38
S
ilv
e
r
d
a
le
R
o
a
d
R
u
a
k
u
r
a
R
o
a
d
AS127
AS128
AS130
AS131
AS132
AS133
AS134
AS135
AS136
AS137
AS138
AS139
AS140
AS141
AS142
AS143
AS144
BH104
BH105
BH106
BH107
BH108 DEEP
BH108 SHALLOW
BH109
BH110
BH111
BH112
CPT104
CPT105
SCPT103
TP109
TP110
TP111
TP112
TP113
TP114
TP115
TP116
3
8
3
9
3
8
3
8
3
7
3
8
3
7
3
9
3
8
Approved Revision DateRevision Amendment
LEGEND
INLAND PORT ZONE
BUSINESS ZONE STAGE 1
BOREHOLE
CPT
SEISMIC CPT
AUGER SCALA
TEST PIT
APPROXIMATE GROUNDWATER
CONTOUR LEVEL FOR SHALLOW
PIEZOMETERS [BASED ON 3/5/13
MONITORING RESULTS]
SLIGHT VARIATION IN CONTOURS
POSSIBLY AFFECTED BY
TOPOGRAPHICAL EFFECTS
OR ABSTRACTION?
500
1:5000
0 10050 150 350200 250 300 400 450
m
@ A1
@ A31:10000
200
100
5010
0mm
300
mm
ScaleProject No. Drawing No. Sheet. No.
Project
Sheet
Revision
Original Sheet Size A1 [841x594] Plot Date 26 Jun 2013 @ 9:05 a.m. Path G:\232100\32113_00 Ruakura TGH\Drawings\CAD\Interpretive Report\2_1826_5_5204_FIG_13-15.dwg FIG.15
Drawn Approved Revision DateDesigned
Hamilton Office Private Bag 3057Hamilton 3240New Zealand+64 7 838 9344
TAINUI GROUP HOLDINGS LTDSTAGE 1 GEOTECHNICAL INVESTIGATIONSRUAKURA DEVELOPMENT
FIGURE 15: GROUNDWATER CONTOUR PLAN: INLAND PORT ZONE, BUSINESS ZONE TO SOUTH
2/1826/5/5204 FIG.15 R1232113.00 1:5000 [A1] 1:10000 [A3]
G.M.B. 22May13
AGRESEARCH
39
39
38
38
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170
Pla
sti
cit
y I
nd
ex
Liquid Limit
Plasticity Chart
SiltHigh plasticity
A-lineClay
High plasticity
ClayLow plasticity
Soil Classification Chart
FIGURE 16
May 2013
Ruakura Stage 1: Geotechnical Interpretive Report
TGH Ltd
SiltLow plasticity
00.5
11.5
22.5
33.5
44.5
55.5
66.5
77.5
88.5
99.510
10.511
11.512
12.513
13.514
14.515
15.516
16.517
17.518
18.519
15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155
Dep
th (
m b
gl)
MC, PL, LL %
Moisture Content LL PL Chart
PL
LL
WCMoisture Content LL PL Chart
Residential Zone Stage 1
FIGURE 17
May 2013
Ruakura Stage 1: Geotechnical Interpretive Report
TGH Ltd
0
0.5
1
1.5
2
2.5
3
3.5
15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165
Dep
th (
m b
gl)
MC, PL, LL %
Moisture Content LL PL Chart
PL
LL
WCMoisture Content LL PL Chart
Business Zone North of AgResearch Stage 1
FIGURE 19
May 2013
Ruakura Stage 1: Geotechnical Interpretive Report
TGH Ltd
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
6.5
7
7.5
8
8.5
9
9.5
10
10.5
11
11.5
15 20 25 30 35 40 45 50 55 60 65 70 75
Dep
th (
m b
gl)
MC, PL, LL %
Moisture Content LL PL Chart
PL
LL
WCMoisture Content LL PL Chart
Inland Port Zone
FIGURE 18
May 2013
Ruakura Stage 1: Geotechnical Interpretive Report
TGH Ltd
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
6.5
7
7.5
8
8.5
9
9.5
10
10.5
11
11.5
12
15 20 25 30 35 40 45 50 55 60 65
Dep
th (
m b
gl)
MC, PL, LL %
Moisture Content LL PL Chart
PL
LL
WCMoisture Content LL PL Chart
Business Zone South of AgResearch Stage 1
FIGURE 20
May 2013
Ruakura Stage 1: Geotechnical Interpretive Report
TGH Ltd
1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
2.1
2.2
0 10 20 30 40 50
Dry D
en
isty
(t/
m3
)Compaction Data
TP102
TP105
TP109
TP110
TP113
TP115
5% Air Voids line
0% Air Voids line
10% Air Voids line
Compaction Data Chart
FIGURE 21
May 2013
Ruakura Stage 1: Geotechnical Interpretive Report
TGH Ltd
MC %
- Sandy SILT
- Silty SAND
- SAND, minor
silt clay and
gravel
- Silty SAND
- Silty SAND
- SAND, minor
silt and clay
DJH
MNP