GEOENVIRONMENTAL SITE INVESTIGATION REPORT PHASE II ...

GEOENVIRONMENTAL SITE INVESTIGATION REPORTPHASE II GEOENVIRONMENTAL SITE INVESTIGATION

OF LAND ATLEXHAM GARDENS

LONDON

Prepared for: -

Madigan Brown18 Chelsea Manor Street,

London,SW3 3UH

On Behalf of: -

Dr. Dennis Xavier8 Cheniston Gardens

LondonW8 6TQ

GeoCon Site Investigations LtdSuite 8 Marple House,39 Stockport Road,MarpleStockportSK6 6BD

February 2016

Ref: F0364 IW (GSI0525) GI Report GG MB 020216

F0364 IW (GSI0525) GI Report GG MB 020216 i February 2016

Quality Assurance

Report Title Ground Investigation Report, Phase II Geotechnical Site Investigation,and Interpretative Report, on land at Lexham Gardens, London.

Report Reference F0364 IW (GSI0525) GI Report GG MB 020216

Client

On Behalf of

Madigan Brown

Dr. Dennis Xavier

Version Revision A

Status Final

Date of First Issue January 2016

Revision Date -

Written byIan Walker

For and on behalf of GeoCon Site Investigations Ltd

Ian Walker B.Sc. (Hons) F.G.S Director

Checked byChris Buckley


Chris Buckley B.Sc. (Hons) Principle Engineer

Authorised byIan Walker


Ian Walker B.Sc. (Hons) F.G.S Director

F0364 IW (GSI0525) GI Report GG MB 020216 ii February 2016

This document has been prepared for the titled project (or named part thereof) and should not be relied upon or used for any other project

without an independent check being carried out as to its suitability and prior written authorization being obtained from GeoCon. GeoCon

accepts no responsibility or liability for the consequences of the use of this document, wholly or in part, for any other purpose than that for

which it was commissioned. Any persons using or relying upon this document for such other purpose do so at their own risk.

This report was prepared for the sole use of the named Client, as defined above, and shall not be relied upon or transferred to any other

party without the express written authorisation of GeoCon. It may contain material subject to copyright or obtained subject to license;

unauthorised copying of this report will be in breach of copyright/license.

From herein after GeoCon Site Investigations Ltd will be referred to as GeoCon.

GeoCon Offices:

Manchester (Head Office)15 Belmont DriveMarple BridgeStockportGreater ManchesterSK6 5EATel: 0844 504 3901

Newcastle-Upon-Tyne:

The Axis Building,

Maingate, Kingsway North,

Team Valley,

Gateshead,

NE11 0NQ

Tel: 0844 504 7981

Birmingham2nd Floor,Quayside Tower,Broad Street,Birmingham.B1 2HFTel: 0844 504 6901

Bristol:

2430 / 2440

The Quadrant,

Almondsbury,

Bristol,

BS32 4AQ

Tel: 0844 504 9208

London (East)Fortis House160 London Rd,BarkingLondonIG11 8BBTel: 0844 504 7901

London (West)

Building 3 Chiswick Park,

566 Chiswick High Road,

Chiswick,

London,

W4 5YA

Tel: 0844 504 4901

F0364 IW (GSI0525) GI Report GG MB 020216 i February 2016

Table of Contents

1.0 INTRODUCTION ..................................................................................................................................5

1.1 Instruction...............................................................................................................................51.2 Scope of Works .......................................................................................................................51.3 Limitations...............................................................................................................................5

2.0 SITE LOCATION AND DESCRIPTION .....................................................................................................7

2.1 Site Location............................................................................................................................72.2 Site Description.......................................................................................................................72.3 Site Usage................................................................................................................................72.4 Future Site Usage ....................................................................................................................72.5 Surrounding Area ....................................................................................................................72.6 Statutory Services ...................................................................................................................72.7 Site Reconnaissance................................................................................................................7

3.0 GROUND INVESTIGATION...................................................................................................................8

3.1 General....................................................................................................................................83.2 Windowless Sample Boreholes...............................................................................................83.3 Sampling and Insitu Testing ....................................................................................................83.4 Installations and Backfill .........................................................................................................93.5 Groundwater...........................................................................................................................93.6 Groundwater Monitoring........................................................................................................93.7 Laboratory testing...................................................................................................................9

4.0 GROUND CONDITIONS .....................................................................................................................10

4.1 Published Geology ................................................................................................................104.2 General..................................................................................................................................104.3 Made Ground........................................................................................................................104.4 Kempton Park Gravel Formation ..........................................................................................104.5 Bedrock (London Clay Formation) ........................................................................................114.6 Groundwater.........................................................................................................................114.7 Obstructions..........................................................................................................................114.8 Contamination ......................................................................................................................11

5.0 GEOTECHNICAL TESTING AND RESULTS............................................................................................12

5.1 General..................................................................................................................................125.2 Geotechnical Testing.............................................................................................................12

6.0 GEOTECHNICAL ASSESSMENT...........................................................................................................14

6.1 General..................................................................................................................................146.2 Geotechnical Model..............................................................................................................146.3 Foundations ..........................................................................................................................156.4 Floor Slabs.............................................................................................................................156.5 Concrete................................................................................................................................156.6 Groundwater and Excavations..............................................................................................156.7 Road Pavement.....................................................................................................................166.8 Sustainable Drainage ............................................................................................................16

7.0 OTHER POTENTIAL DEVELOPMENT CONSIDERATIONS......................................................................17

7.1 Waste Soils Characterisation ................................................................................................177.2 Imported Fill..........................................................................................................................177.3 Construction Activities ..........................................................................................................17

8.0 References .........................................................................................................................................1

F0364 IW (GSI0525) GI Report GG MB 020216 ii February 2016

LIST OF TABLES

TABLE 3.1 GROUNDWATER MONITORING STANDPIPE ........................................................................................................ 9

TABLE 4.1: PUBLISHED GEOLOGY................................................................................................................................. 10

TABLE 5.1: INSITU GEOTECHNICAL TESTING ................................................................................................................... 12

TABLE 5.2: GEOTECHNICAL LABORATORY ANALYSIS......................................................................................................... 12

TABLE 5.3: ATTERBERG LIMITS TESTING RESULTS............................................................................................................ 12

TABLE 5.4: SUMMARY OF BRE SD 1 RESULTS................................................................................................................ 13

TABLE 6.1: SUMMARY OF GROUND CONDITIONS ............................................................................................................ 14

F0364 IW (GSI0525) GI Report GG MB 020216 iii February 2016

APPENDICES

Appendix Information

A Drawings

B Windowless Sample Borehole Logs

C Hand Pit Logs

D Hand Pit Sketches and Photographs

E Geotechnical Testing Results

F0364 IW (GSI0525) GI Report GG MB 020216 iv February 2016

LIST OF ACRONYMS

Acronym Meaning

BGS British Geological Survey

BH Borehole

CDM Construction Design and Management

CL:AIRE Contaminated Land: Applications In Real Environments

CLR Contaminated Land Report

COSHH Control Of Substances Hazardous to Health

CSM Conceptual Site Model

DCP Dynamic Cone Penetrometer

DEFRA Department for Environment Foods and Rural Affairs

DP Dynamic Probe

DOE Department Of Environment

DWS Drinking Water Standard

EA Environment agency

EQS Environmental Quality Standard

GAC Generic Acceptance Criteria

HP Hand Pit

HA Hand Auger

LQM Land Quality Management

mbgl Meters Below Ground Level

MP Mackintosh Probe

NGR National Grid Reference

OS Ordnance Survey

SGV Soil Guideline Value

SSV Soil Screening Value

WSV Water Screening Value

SPOSH Significant Possibility of Significant Harm

SPZ Source Protection Zone

SSSI Site of Special Scientific Interest

TP Trial Pit

TT Trial Trench

WS Windowless Sample / Window Sample

F0364 IW (GSI0525) GI Report GG MB 020216 5 February 2016

1.0 INTRODUCTION

1.1 Instruction

1.1.1 GeoCon Site Investigations Ltd (to be referred to as GeoCon from hereon in) have been commissionedby Madigan Brown (to be referred to as MB from hereon in) on behalf of Dr. Dennis Xavier to undertakea Phase II Geoenvironmental Site Investigation on Land at Lexham Gardens, London.

1.1.2 This report is prepared to provide details of the engineering properties of the soils beneath the site inorder to facilitate foundation design for the proposed development.

1.1.3 At this stage GeoCon have not been commissioned to carry out a Phase I Preliminary Risk Assessmentor any Phase II Contamination Investigation, and have not been provided with any third party reports.

1.2 Scope of Works

1.2.1 It should be noted that the scope of works was provided by MB.

Phase II

One windowless sample boreholes to a nominal depth of up to 8.00mbgl or refusal.

Four hand excavated trial pits to a maximum depth of 1.20mbgl, to expose the existingfoundations.

Insitu geotechnical and geoenvironmental testing and sampling.

Full supervision of all works by engineering geologist including sampling and detailedgeotechnical descriptions to BS5930, EN ISO 14688-1 EN ISO 14688-2 and EN ISO 14689 of allstrata types encountered within the exploratory holes.

A suite of geotechnical laboratory analysis.

Production of an interpretative report.

1.3 Limitations

1.3.1 The assessment and interpretation of the factual data obtained as part of this Phase II Site Investigationhas been undertaken in accordance with standard consulting practise and with current national andinternational guidance.

1.3.2 This report presents the observations made during the Phase I Preliminary Site Investigation and PhaseII Site Investigation and the factual data obtained. The conclusions and recommendations in this reportare limited to those which can be made based on the findings of the survey and information providedby third parties. GeoCon assumes all third party data to be true and correct. No responsibility can beaccepted by GeoCon for inaccuracies in the information provided by any other party.

1.3.3 This report is written in the context of an agreed scope of works and should not be used in a differentcontext. Furthermore, new information, improved practises, and changes in legislation may require thereinterpretation of the report in whole or in part after its original issue. GeoCon reserve the right to altertheir conclusions and recommendations in the light of further information that may become available.This report is provided for the sole use of the client and their professional advisers and is confidential tothem unless agreed otherwise in writing.

1.3.4 Ground conditions can be variable and change rapidly, especially in areas of Made Ground, however itis assumed that the ground conditions encountered and observed are typical and representative of thesite as a whole. Most specifically with regard to this limited investigation, the ground conditions havebeen determined from a limited number of exploratory holes formed across the site, therefore only asmall percentage of the total area of the site has been investigated. Interpolation between exploratoryholes has enabled a general picture of the subsurface conditions to be produced. Conclusions drawn


from the ground investigation should be read in this context. GeoCon cannot accept responsibility forany situations resulting from locally unforeseen ground conditions occurring between exploratory holes.

1.3.5 In addition, subsurface conditions including contaminant concentrations and groundwater levels mayvary spatially with time. This factor should be given due consideration in the event that the informationcontained within this report is used after any significant period of time has elapsed.


2.0 SITE LOCATION AND DESCRIPTION

2.1 Site Location

2.1.1 The site is located at 120 Lexham Gardens, London at approximate National Grid Reference NGR:525439:178984 (centre of the site).

2.1.2 A site location plan is presented as Drawing No. GSI0525/01 in Appendix A.

2.2 Site Description

2.2.1 The site is an irregular shaped piece of land comprising 120 Lexham Gardens, and is currently coveredby the existing property and rear garden, which comprises a mixture of existing buildings, hardstandingand grassed landscaped areas.

2.2.2 The site is situated within an existing residential area and is bound by neighbouring residential propertiesin all directions.

2.2.3 The topography of the site is generally flat.

2.2.4 Access to the site is via Lexham Gardens from the south.

2.3 Site Usage

2.3.1 The site is currently occupied by the existing residential property.

2.4 Future Site Usage

2.4.1 It is understood that the proposed development will comprise the amalgamation of two existing lowerground floor flats and the construction of a new basement, below the existing lower ground floor.

2.5 Surrounding Area

2.5.1 The current surrounding land use to the site is generally residential properties in all directions.

2.5.2 The topography of the surrounding area is generally flat.

2.6 Statutory Services

2.6.1 GeoCon were provided with copies of the buried service location plans, which were used to help positionall exploratory holes in areas free from buried services.

2.7 Site Reconnaissance

2.7.1 A site walkover was carried out on 10th December 2016. All details from the site walkover are includedin the site description above. There are no further relevant details above those which are already givenin this report.


3.0 GROUND INVESTIGATION

3.1 General

3.1.1 The intrusive investigation was carried out on 10th December 2016.

3.1.2 The specification and scope of works for the ground investigation has been provided by the client.

3.1.3 The ground investigation has been carried out in accordance with BS5930 and the UK Specification forGround Investigation Second Edition 2012.

3.1.4 All strata descriptions were undertaken in accordance with BS5930 Amendment 1; EN ISO 14688 -1; ENISO 14688 -2; and EN ISO 14689.

3.1.5 The actual ground investigation comprised the formation of:

One windowless sample borehole.

Four hand excavated trial pits.

Insitu geotechnical testing and sampling.

Full supervision of all works by engineering geologist including sampling and detailedgeotechnical descriptions to BS5930, EN ISO 14688-1 EN ISO 14688-2 and EN ISO 14689 of allstrata types encountered within the exploratory holes.

The installation of one groundwater monitoring standpipe with subsequent groundwatermonitoring on one occasion.

A suite of geotechnical laboratory analysis.

Production of an interpretative report.

3.1.6 The locations of the exploratory holes were specified by GeoCon and were positioned to gain keyinformation beneath the site in relation to the proposed development.

3.1.7 All locations were checked against buried service plans, scanned with a Cable Avoidance Tool (CAT) priorto excavation and marked out by GeoCon on site who were responsible for issuing a permit to dig ateach location. All locations were then checked again with a Cable Avoidance Tool (CAT) by GeoCon priorto excavation; each location was then continued by hand down to a minimum of 1.20mbgl to clear eachlocation of any buried services or other.

3.1.8 All access permissions were arranged by MB prior to the ground investigation commencing.

3.1.9 An exploratory hole location plan is presented in Appendix A as drawing number GSI0525/02.

3.2 Windowless Sample Boreholes

3.2.1 One windowless sample borehole was drilled at the site using a restricted access rig to gain anunderstanding of the existing ground conditions and soil / rock strengths beneath the site. Thewindowless sample borehole was drilled to a depth of 7.45mbgl, where the hole was terminated due tocollapse of the granular strata.

3.2.2 Insitu Standard Penetration Tests were carried out at 1.00m intervals in all windowless sample boreholeswhere available to collate strength information for the soils beneath the site.

3.2.3 The windowless sample borehole log is presented in Appendix B.

3.3 Sampling and Insitu Testing

3.3.1 The geotechnical and chemical sampling regime and insitu testing regime included the following:

Small disturbed samples taken from each strata type and then at 1.00m intervalsthereafter.


Bulk disturbed samples taken at 1.00m intervals to a depth of 5.00mbgl, then 1.50mintervals thereafter

3.3.2 Soil samples were collected for geotechnical and chemical analysis by the engineering geologist on sitebased on physical and visual inspection in addition to standard sampling, and were subsequentlysampled and transferred to a geotechnical laboratory in prepared bulk bags and plastic tubs.

3.3.3 All samples were stored in pre-chilled cool-boxes prior to immediate dispatch to laboratory. Wherethere has been a delay in transporting the samples to the laboratory, samples have been kept in a cooldark storage unit inside cool boxes packed with ice, which is regularly replaced to maintain samplequality.

3.4 Installations and Backfill

3.4.1 One of the windowless sample boreholes was installed with a ground water monitoring standpipe. Thedetails of the gas and ground water monitoring standpipes are summarised below in Table 3.1:Groundwater Monitoring Standpipe:

3.4.2 Full details of the installations and backfill are presented on the relevant borehole logs.

Table 3.1 Groundwater Monitoring Standpipe

BH ID Installation Depth

(mbgl)

Response Zone (mbgl) Installation Date Comments

WS01 5.00 1.00 – 5.00 10/12/2015 NA

3.4.3 All monitoring standpipes are constructed using 50mm slotted pipe with a Geosock filter and gravelsurround medium within the response zone, and 50mm plain pipe with a bentonite seal above theresponse zone (minimum 0.50m thick).

3.4.4 All remaining exploratory holes were backfilled with arisings and made level at the surface to a similarcondition as prior to the work.

3.5 Groundwater

3.5.1 Where groundwater was encountered a waiting period of 20 minutes was allowed to monitor anychange (rise or fall) in the levels of each groundwater strike.

3.6 Groundwater Monitoring

3.6.1 Groundwater monitoring was carried out on one occasion and the results are given in Section 4.0 of thisreport.

3.6.2 No long term groundwater monitoring has been carried out at this stage based on the scope of worksprovided by MB.

3.7 Laboratory testing

3.7.1 Geotechnical laboratory testing was subsequently carried out on selected samples of soil. Further detailsof the geotechnical laboratory testing are given within section 5.0 – Geotechnical Testing and Results.

3.7.2 All geotechnical laboratory testing was scheduled by GeoCon.


4.0 GROUND CONDITIONS

4.1 Published Geology

4.1.1 The British Geological Survey (BGS) Map Sheet 270 South London solid and drift editions, and the BGSOnline Open Geoscience shows the site to be underlain by the following geological succession outlinedbelow in Table 4.1: Published Geology.

Table 4.1: Published Geology

Geology Description /strata

Artificial None recorded

Superficial Kempton Park Gravel Formation

Bedrock London Clay Formation

4.1.2 There is no known artificial ground indicated to underlie the site.

4.1.3 The superficial deposits indicated underlying the site are shown to be the London Kempton Park GravelFormation which is generally described as ‘sand and gravel, locally with lenses of silt, clay or peat’ (BGSgeneral description).

4.1.4 The bedrock geology beneath the site is shown to be the London Clay Formation which is generallydescribed as ‘bioturbated or poorly laminated, blue-grey or grey-brown, slightly calcareous, silty to verysilty clay, clayey silt and sometimes silt, with some layers of sandy clay. It commonly contains thin coursesof carbonate concretions (‘cementstone nodules’) and disseminated pyrite. It also includes a few thinbeds of shells and fine sand partings or pockets of sand, which commonly increase towards the base andtowards the top of the formation. At the base, and at some other levels, thin beds of black rounded flintgravel occurs in places. Glauconite is present in some of the sands and in some clay beds, and white micaoccurs at some levels’ (BGS general description).

4.2 General

4.2.1 The actual ground conditions encountered across the site were generally uniform and comprised madeground overlying sand & gravel. The general ground conditions encountered have been summarisedbelow.

4.2.2 Detailed strata descriptions are presented on the windowless sample borehole log and the hand pit logspresented in Appendix B and C respectively.

4.3 Made Ground

4.3.1 Made ground was encountered in all exploratory hole locations from ground level to depths of between0.38 and 4.60mbgl. Within the hand pits the made ground was not penetrated.

4.3.2 The made ground generally comprised a mixture of hardstanding (ceramic tiles and paving flag) and grassat the surface, overlying horizons of cohesive and granular made ground.

4.3.3 The granular made ground general comprised gravelly sand, with fragments of brick and slate.

4.3.4 The cohesive made ground general comprised sandy gravelly clay, with fragments of brick, slate, clinkerand concrete.

4.4 Kempton Park Gravel Formation

4.4.1 Materials considered to represent Kempton Park Gravel Formation were encountered directly beneaththe made ground and were proven to a depth of 6.00mbgl. No recovery was achieved between 6.00and 7.45mbgl due to the collapse of the granular strata.

4.4.2 The Kempton Park Gravel Formation generally comprised medium dense gravelly sand, becoming loosebelow 6.00mbgl.


4.5 Bedrock (London Clay Formation)

4.5.1 Bedrock was not encountered during this ground investigation.

4.6 Groundwater

4.6.1 No groundwater was encountered during the ground investigation.

4.6.2 Groundwater monitoring was carried out on one occasion and the standing water level was recorded at5.15mbgl in WS01 and the base of the installation was dipped at 5.23mbgl.

4.6.3 No long term groundwater monitoring has been carried at this stage based on the scope of worksprovided by the client.

4.7 Obstructions

4.7.1 No obstructions were encountered during this ground investigation, however all windowless sampleboreholes refused at shallow depths within the dense compacted sands beneath the site.

4.8 Contamination

4.8.1 Although this report in not for contamination purposes, it should be noted that no obvious visual orolfactory evidence of contamination was encountered or observed during this ground investigation, withthe exception of general made ground materials.


5.0 GEOTECHNICAL TESTING AND RESULTS

5.1 General

5.1.1 This geotechnical investigation was undertaken to provide details of the ground conditions, soilsstrengths, engineering properties of the soils and rock beneath the site, and subsequent advice onsuitable foundation solutions.

5.1.2 It should be noted that GeoCon have not been provided with any further details regarding the structuralloading at this stage.

5.2 Geotechnical Testing

5.2.1 In-situ Standard Penetration Tests (SPTs) were undertaken in accordance with BS1377 (1990) within thewindow sample boreholes. A summary of the insitu testing is given below in Table 7.1 InsituGeotechnical Testing:

Table 5.1: Insitu Geotechnical Testing

Strata SPT N Value Range Locations Encountered

Made Ground 7 – 16 All locations

Kempton Park Gravel Formation 5 – 14 WS01

NR = Not Recorded In This Strata

5.2.2 A programme of geotechnical laboratory testing was undertaken in accordance with BS1377 (1990)‘Methods of tests for soils for civil engineering purposes. The geotechnical testing regime has beensummarised below in Table 5.2 Geotechnical Laboratory Analysis.

Table 5.2: Geotechnical Laboratory Analysis

BS 1377 Test Number Test Description Quantity Analysed

BS 1377 1990: Part 2. Clause 3.2 Moisture Content 2

BS 1377 1990: Part 2. Clause 4.3 & 5.3 Atterberg Limits 2

BS 1377 1990: Part 2. Clause 9.2 PSD Wet Sieve Method 1

BS 1377 1990: Part 3. Clause 5.3 & BRE CP2/79 BRE SD 1 3

5.2.3 The results of the geotechnical testing are presented in Appendix E.

Plasticity Index

5.2.4 Atterberg limit testing was carried out on selected samples of cohesive soils taken from the site toestablish the plasticity index of the clay made ground beneath the site. The results of this testing ispresented below in Table 5.3 Atterberg Limits Testing Results.

Table 5.3: Atterberg Limits Testing Results

Test Range

Moisture Content (%) 14 – 20

Liquid Limit (%) 38 – 41

Plastic Limit (%) 15 – 16

Plasticity Index (%) 23 – 25

Modified plasticity index (%) 20.01 – 22.75

5.2.5 Based on these results the clay made ground beneath the site can be classed as intermediate plasticity.


5.2.6 Chapter 4.2 ‘Building near Trees’ of the NHBC standards indicates that from the testing results, themodified plasticity index is between 20.01 and 22.75% and therefore, the clay beneath the site is ofmedium volume change potential.

BRE SD 1

5.2.7 Three soil samples were analysed for BRE SD 1 reduced suite to assess the risk to buried concrete at thesite, which includes total sulphate, water soluble sulphate, pH and total sulphur. In addition, threesample was analysed for water soluble sulphate and pH as part of the chemical and these results havebeen included in the assessment below. The results of the testing are summarised below in table 5.4Summary of BRE SD 1 Results.

Table 5.4: Summary of BRE SD 1 Results

Test Soil Test - Results Range

Total sulphate (%) 0.23 – 0.27

Water soluble sulphate (mg/l) 10 – 20

Total sulphur (%) 0.01 – 0.02

pH 7.69 – 7.77

Total Potential Sulphate (%) 0.03 – 0.06

Potential amount of Oxidisable Sulphate Present (%) -0.2 – -0.21

5.2.8 Design/mix of buried concrete should be undertaken in accordance with the “Aggressive ChemicalEnvironment for Concrete” (ACEC) classification, of BRE Special Digest 1:2005 (Concrete in AggressiveGround).

5.2.9 Total potential sulphate has been calculated from the above information and gives a range of between0.03% and 0.06%.

5.2.10 Oxidisable sulphides have then been calculated in the range of -0.02% and -0.21%.

5.2.11 The above results indicate that pyrite is unlikely to be present within the soils beneath the site.

5.2.12 A review of the pH and sulphate concentrations indicates that all concrete used in the foundations atthis site should be designed to “Design Sulphate Class” DS-1, and the “Aggressive Chemical Environmentfor Concrete” (ACEC) class AC-1.

Particle Size Distribution

5.2.13 One sample was analysed for PSD to confirm field descriptions and for use by any piling contractors ifrequired.

5.2.14 Field description have been amended where necessary based on the results of the PSD test.


6.0 GEOTECHNICAL ASSESSMENT

6.1 General

6.1.1 It is understood that the proposed development will comprise the amalgamation of two existing lowerground floor flats and the construction of a new basement, below the existing lower ground floor.

6.1.2 Based on the drawings provided by MB it is understood that the existing party wall with the adjacentstructure will need to be underpinned as part of the construction work.

6.1.3 The recommendations given below assume that ground levels intended for the redevelopment will besimilar to those existing at present. If ground levels are subject to significant change as part of theproposed development, then the recommendations made below may require reinterpretation.

6.1.4 At this stage GeoCon have not been provided with any loadings for the proposed development.

6.2 Geotechnical Model

6.2.1 One window sample borehole was formed in the garden to the rear of the existing property, over thearea of the proposed basement extension. Additionally, four hand excavated trial pits were undertakenadjacent to the existing property, to investigate the depth and nature of the existing foundations.

6.2.2 The ground conditions encountered within the exploratory holes are summarised below in Table 6.1:Summary of Ground Conditions.

Table 6.1: Summary of Ground Conditions

Stratum Depth Range toBase of Stratum

(mbgl)(Thickness Range)

Strength/Consistency Notes

Topsoil and Made Ground

Made Ground 4.60 (4.60) SPT N values in the range 7-16,no particular depth correlation

apparent

Described as soft becoming very stiff sandy gravellyclay.

Hand dug trial pits recorded Made Ground comprisingsoft gravelly clay or clayey gravelly sand to amaximum depth of 1.20mbgl.

Atterberg & Moisture Content Tests (2no. samplesanalysed)

Moisture Contents – 14% to 20%

Plastic Limits – 15% to 16%

Liquid Limits – 38% to 41%

Plasticity Indices* - 20% to 23%

Natural Strata

Sand and Gravel 6.00m (1.40) A single SPT N value of 14 wasrecorded in WS01 at 5.00mbgl,corresponding with a medium

dense stratum

A tentative phi value of 34° isproposed for the stratum based

on the field data, in-situ testresults and laboratory data

A particle size distribution test recorded 21% silt andclay, 60% sand and 19% gravel.

UnknownUnderlyingStrata

>7.00m (1.00m+) SPT N values of 5 were recordedat 6.00mbgl and 7.00mbgl,corresponding to a loosegranular material, or low

strength clay

The stratum was not recovered in WS01, which wasterminated due to collapse of the granular materialsencountered in the borehole.


* - Corrected for fines content in accordance with NHBC Chapter 4.2.

6.2.3 The Atterberg Limits test results demonstrate that the Made Ground can be generally classified as clayof intermediate plasticity and medium volume change potential.

6.2.4 The bulk density of the Made Ground and sand and gravel deposits is likely to be in the order of 19kN/m3,based on field observations and experience of similar materials.

6.2.5 No water strikes were recorded during drilling. Groundwater levels recorded during a singlegroundwater monitoring visits were subsequently recorded as 5.15mbgl.

6.2.6 Hand dug trial pits adjacent to the existing building recorded the underside of the foundations at depthsof 0.15mbgl to 0.58mbgl. The existing footings therefore appear to be situated on the Made Ground.

6.3 Foundations

6.3.1 Section drawings supplied by the Architect for the project indicate that the proposed basement willunderlie the existing lower ground floor and will be at least 3.50mbgl.

6.3.2 It is understood that the basement and its foundations will not be carrying any loads from the overlyingstructure and that the underpinned party wall will not carry any additional loads. If this is the case, thenthere should be no increase in the net bearing pressure on the existing formation imposed by thebasement construction. If this is not to be the case, then a more detailed assessment should beundertaken, particularly as the excavation / underpinning is likely to be within Made Ground and also,due to the low SPT N values recorded below 6.00mbgl.

6.3.3 Interactions between new and existing foundations would need to be considered, as would the potentialfor differential settlement between new and existing structures. A construction joint should beincorporated at the interface between any new and existing structures. Particular care will be requiredto ensure that the new basement does not adversely impact the existing foundations.

6.3.4 Once excavated, the formation may be subject to heave, which may result in settlement when the newfoundation loads are applied. The designer should ensure that any settlement would remain withinserviceable limits for the new and existing structures.

6.3.5 Foundation depths may need to be increased where they are within influencing distance of trees. Heaveprecautions may also be required. Advice on these issues is given in NHBC Standards Chapter 4.2.

6.4 Floor Slabs

6.4.1 A ground bearing floorslab for the basement could be placed at the proposed formation level, subject toproof rolling and the removal of any unsuitable materials.

6.5 Concrete

6.5.1 A review of the pH and sulphate concentrations indicates that all concrete used in the foundations atthis site should be designed to “Design Sulphate Class” DS-1, and the “Aggressive Chemical Environmentfor Concrete” (ACEC) class AC-1.

6.6 Groundwater and Excavations

6.6.1 Based on the monitoring carried out to date, groundwater levels may remain below the excavation levelfor the proposed basement construction. However, groundwater levels are subject to seasonalvariations and higher levels could be present, particularly during prolonged periods of wet weather.Groundwater levels above the basement excavation level could result in piping of the formation layer,which could result in foundation failure during construction. It is therefore recommended that thegroundwater levels are monitored during construction to ensure that they remain below the base of theproposed excavation at all times. If groundwater levels were to rise above the proposed excavationlevel, then they would need to be artificially reduced in advance of the excavation, using either well


points or possibly sump pumps. Advice on Groundwater Control is given in CIRIA Report No. 515 –Groundwater Control Design and Practice.

6.6.2 With respect to buoyancy effects / hydrostatic water pressure, in the absence of long term groundwaterlevel monitoring data, it is recommended that a design groundwater level of 0.00mbgl is adopted forbasement design purposes. The structural design engineer should check that the stiffness of thefloorslab is sufficient to resist bending due to potential groundwater uplift pressures, and that thestructure is heavy enough to resist buoyancy effects.

6.6.3 Excavations should be feasible using conventional plant.

6.6.4 Excavations would need to be fully supported at all times. Temporary works design will need to takeinto account the additional loads imposed by the existing structures adjacent to the excavation and toensure that no movement takes place due to the removal of lateral support caused by the basementexcavation. Advice on excavation support is given in CIRIA Report No 97 – Trenching Practice.

6.7 Road Pavement

6.7.1 Any new pavements will require assessment of the existing sub grade in terms of its California BearingRatio (CBR) to facilitate the actual pavement design. However, it is understood that no new roads /pavements will be incorporated into the proposed development.

6.8 Sustainable Drainage

6.8.1 In accordance with PPS25 (2007), the Planning Authority are likely to insist that surface water drainagefrom any new-build or redevelopment complies with current design practices for Sustainable UrbanDrainage (SUD’s), with the construction of separate drainage systems for foul and surface water. Surfacewater shall be required to be attenuated reducing the discharge of water from the site requiringtreatment and disposal. A 20% reduction in surface water discharge rates off the site is to be expected– allowing for the 1 in 100 year storm event and allowing for climate change.

6.8.2 Based on the ground conditions encountered it is unlikely that sustainable drainage would be suitableat the site. If sustainable drainage is to be considered, it is recommended that soak-away testing iscarried out in accordance with BRE 365 at the site to establish the sites suitability for sustainabledrainage.


7.0 OTHER POTENTIAL DEVELOPMENT CONSIDERATIONS

7.1 Waste Soils Characterisation

7.1.1 Any excavation works may potentially produce waste soils for which appropriate waste managementwill be required. At this stage it is not possible to classify the likely waste category. Any off-site disposalof soil requires careful management and due consideration of appropriate legislation, guidance and Dutyof Care responsibilities.

7.1.2 Waste Acceptance Criteria (WAC) testing should be carried out on samples of any materials requiringdisposal from site. The results of the WAC testing should be presented to the landfill operator for theirconfirmation of waste category.

7.2 Imported Fill

7.2.1 Any imported fill will be subject to specific quality requirements, particularly in any proposed areas oflandscaping. Allowance should be made for the testing of imported fill materials prior to emplacementto ensure suitability should the materials be delivered with no testing certification.

7.3 Construction Activities

7.3.1 Due consideration should be given to the suppression of noise, dust and vibration emissions from thesite during construction.


8.0 REFERENCES

AGS: A clients guides and tool kit

Atkins: AtRisk Soil Screening Values and Water Screening Values

Bowles, J. E. (1996): Foundation analysis and design, McGraw-Hill, New York.

British Geological Survey (BGS): 1:50’000 geological maps of the area

British Geological Survey (BGS): Open geoscience online mapping tool

BS 5930: code of Practise for Site Investigation Amendment 2

BS 10175: Code of Practise for the Investigation of Potentially Contaminated Sites

BRE 410 (2004): Working platforms for tracked plant: Good practice guide to the design, installation, maintenance and repair

of ground-supported working platforms, BRE Press, Garston.

BRE 211 Radon: Guidance on protective measures for new buildings

CIRIA 552: Contaminated Land Risk Assessment; A Guide to Good Practise 2001

CIRIA 665: Assessing the Risks Posed by Hazardous Ground Gases for Buildings 2007

Coal Authority: Coal authority mining report and Cheshire brine subsidence report

Contaminated Land: Applications in Real Environments (CL:AIRE): ‘The Soil Generic Assessment Criteria for Human Health Risk

Assessment’ GAC’s.

David Norbury: Soil and Rock Descriptions in Engineering Practise

Department of the Environment: DOE industry profiles

EN ISO 14688-1: Geotechnical investigation and testing -- Identification and classification of soil -- Part 1: Identification and

description

EN ISO 14688-2: Geotechnical investigation and testing -- Identification and classification of soil -- Part 2: Principles for a

classification

EN ISO 14689: Geotechnical investigation and testing -- Identification and classification of rock -- Part 1: Identification and

description

Environment Agency (EA): EA Online & What’s in my back yard

Environment Agency (EA): Soil Guideline Values (SGVs)

International Society of Rock Mechanics (ISRM): Commission on Testing Methods (1985) Suggested Method for Determining

Point Load Strength, Int. J. Rock Mech. Min. Sci. and Geomech. Abstr. 22, 1985, pp.51-60.

Land Quality Management (LQM): Generic Screening Criteria (GACs)

Landmark: Envirocheck report and Envirocheck analysis online historical mapping tool

Ordnance survey: OS Landranger map for the area; OS open data online mapping tool

Planning Policy 23: Planning and Pollution Control, Office of The Deputy Prime Minister 2004

R&D Publication CLR 8: Assessment of risks to human health from land contamination

R&D Publication CLR 10: The Contaminated Land Exposure Model (CLEA)

R&D Publication CLR 11: Model Procedure for the Management of Contaminated Land DEFRA 2004

Stroud M.A: The standard penetration test in insensitive clays, Proceedings of the European Symposium on Penetration Testing,

Stockholm, 1975, Vol 2,pp 367 – 75.

UK Specification for Ground Investigation Second Edition 2012

APPENDIX A

DRAWINGS

GeoCon Site Investigations LtdSuite 8 Marple House,39 Stockport Road,Marple,Stockport,SK6 6BD.Tel: 0844 504 3901, Fax: 0844 504 3902,Email: [email protected]: www.geoconsiteinvestigations.com

SITE NAME/CONTRACT

Lexham Gardens, London

DRAWING NO.

GSI0525/01

SCALE

N.T.S

TITLE

Site Location Plan

DATE

February 2016

DRAWN BY

IW

N

GeneralSite

Location

GeoCon Site Investigations LtdSuite 8 Marple House,39 Stockport Road,Marple,Stockport,SK6 6BD.Tel: 0844 504 3901, Fax: 0844 504 3902,Email: [email protected]: www.geoconsiteinvestigations.com

SITE NAME/CONTRACT


DRAWING NO.

GSI0525/02

SCALE

N.T.S

TITLE

Exploratory Hole Location Plan

DATE

February 2016

DRAWN BY

IW

N

Legend:

WS01

Windowless Sample Borehole Location

Hand Pit Location

HP03

HP04

HP02

HP01

APPENDIX B

WINDOWLESS SAMPLE BOREHOLE LOG

Client: Dr. Dennis Xavier

Project: Lexham Gardens, London.

Number: GSI 0525

ES

EW

Environmental Sample- Soil

Environmental Sample- Water

SOIL & ROCK DESCRIPTIONSAll soils and rock descriptions were undertaken inaccordance with BS5930 Amendment 1;EN ISO 14688 -1; EN ISO 14688 -2;and EN ISO 14689.

Water Rise Level after 20minutes

ABBREVIATIONS

(Unified Soil Classification System)LITHOLOGIC SYMBOLS

MADE GROUND: MADE GROUND

CONCRETE: CONCRETE

SAND cl gr: Clayey gravelly SAND

KEY TO SYMBOLS

-

-

-

-

-Water Level After 24 Hours,or as Shown

Water Level at Time of Strike

BACKFILL / WELL SYMBOLS

Bentonite Seal: 1 pipe group, 1 pipe

Slotted Pipe: 1 pipe group, 1 pipe

Slough at bottom of hole

D

B

BD

S

U

Small Disturbed Sample

Bulk Disturbed Sample

Bulk & Small Disturbed Sample

Standard Penetration Test

Undisturbed Sample

GeoCon Site Investigations Ltd15 Belmont Drive, Marple Bridge, Stockport. SK6 5EATel: 08445043901 Fax: 08445043902Web: www.geoconsiteinvestigations.comEmail: [email protected]

1.20-1.65 SPT N7

1.50 D

2.00-2.45 SPT N16

2.50 D

3.00-3.45 SPT N12

3.50 D

4.00-4.45 SPT N12

4.50 D

4.70 D

5.00-5.45 SPT N14

5.50 D

6.00-6.45 SPT N5

7.00-7.45 SPT N5

0.40

1.00

4.60

5.10

6.00

7.45

(0.40)

(0.60)

(3.60)

(0.50)

(0.90)

(1.45)

MADE GROUND: Grass over, soft brown sandy gravelly CLAY, withoccasional roots and rootlets. Gravel is angular to subrounded fine tocoarse of flint slate brick and timber.(TOPSOIL)MADE GROUND: Soft to firm light brown sandy gravelly CLAY. Gravel isangular to subrounded fine to coarse of flint glass brick slate and clinker.

MADE GROUND: Stiff to very stiff orangish light brown sandy gravellyCLAY. Gravel is angular to subangular fine to coarse of brick flint andconcrete.

Orangish light brown slightly clayey slightly gravelly SAND. Gravel isangular to subangular fine to medium of flint.(KEMPTON PARK GRAVEL FORMATION)

Medium dense dark greyish brown slightly clayey to clayey very gravellySAND. Gravel is angular to subangular fine to coarse of flint.(KEMPTON PARK GRAVEL FORMATION)

No Recovery.6.00 Loose below 6.00mbgl.

MG

MG

MG

KPGR

KPGR

Boring Progress and Water Observations

DepthTestResult

CasingDia. mm

WaterDepth ToFrom To

SAMPLES & TESTS STRATA

1 of 1

Chiselling Water Added

Depth TypeNo W

ater

LegendReduced

Level DESCRIPTION

Date Time Depth Depth

(Thick-ness)

Hours From

WINDOWLESS SAMPLE BOREHOLE LOGWINDOWLESS SAMPLE

BOREHOLE No

Inst

rum

ent

& B

ackf

ill

Geo

logy

Date Ground Level (m) Co-Ordinates ()

Contractor

Project ID

Client Method / Plant Used Logged By

GENERAL REMARKS

Project

Sheet

All dimensions in metresScale 1:50

Madigan Brown

GSI 0525

Lexham Gardens, London.

10-12-1510-12-15

WS01

Competitor Dart

Exploratory hole cleared of buriedservices. Hand pit excavated to1.20mbgl. No groundwaterencountered. Terminated due toblowing sands.

Dr. Dennis Xavier Zsuzsa Bella

GeoCon Site Investigations Ltd15 Belmont Drive, Marple Bridge, Stockport SK6 5EA.

Tel: 08445043901 Fax: 08445043902Web: www.geoconsiteinvestigations.com Email: [email protected]

APPENDIX C

HAND PIT LOGS

Client: Dr. Dennis Xavier

Project: Lexham Gardens, London.

Number: GSI 0525

ES

EW

Environmental Sample- Soil

Environmental Sample- Water

SOIL & ROCK DESCRIPTIONSAll soils and rock descriptions were undertaken inaccordance with BS5930 Amendment 1;EN ISO 14688 -1; EN ISO 14688 -2;and EN ISO 14689.

Water Rise Level after 20minutes

ABBREVIATIONS

(Unified Soil Classification System)LITHOLOGIC SYMBOLS

MADE GROUND: MADE GROUND

CONCRETE: CONCRETE

SAND cl gr: Clayey gravelly SAND

KEY TO SYMBOLS

-

-

-

-

-Water Level After 24 Hours,or as Shown

Water Level at Time of Strike

BACKFILL / WELL SYMBOLS

Bentonite Seal: 1 pipe group, 1 pipe

Slotted Pipe: 1 pipe group, 1 pipe

Slough at bottom of hole

D

B

BD

S

U

Small Disturbed Sample

Bulk Disturbed Sample

Bulk & Small Disturbed Sample

Standard Penetration Test

Undisturbed Sample

GeoCon Site Investigations Ltd15 Belmont Drive, Marple Bridge, Stockport. SK6 5EATel: 08445043901 Fax: 08445043902Web: www.geoconsiteinvestigations.comEmail: [email protected]

0.00-0.050.05-0.100.10-1.20

MADE GROUND: White CERAMIC TILES.MADE GROUND: Grey PAVING SLAB.MADE GROUND: Orangish brown slightly gravelly SAND. Gravel is angular to subangular fine tocoarse of flint slate and brick.

B C Legend1 of 1

STRATA

A

C

HAND PIT No

A D

SAMPLES & TESTS

BD

Depth No DESCRIPTION Depth No Remarks/Tests

Shoring/Support:Stability:

0

1

2

0

1

2

HAND PIT LOG


Contractor

Project ID


GENERAL REMARKS

Project

Sheet


Madigan Brown

GSI 0525


10-12-1510-12-15

HP01

Hand Digging Equipment

Exploratory hole cleared of buriedservices. Hand pit excavated to1.20 mbgl. No groundwaterencountered.




0.00-0.050.05-0.60

MADE GROUND: White CERAMIC TILES.MADE GROUND: Orange clayey gravelly SAND. Gravel is angular to subrounded fine to coarse ofconcrete brick and flint.

B C Legend1 of 1

STRATA

A

C

HAND PIT No

A D

SAMPLES & TESTS

BD



0

1

0

1

HAND PIT LOG


Contractor

Project ID


GENERAL REMARKS

Project

Sheet

All dimensions in metresScale 1:12.5

Madigan Brown

GSI 0525


10-12-1510-12-15

HP02


Exploratory hole cleared of buriedservices. Hand pit terminated at0.60 mbgl due to confinedworking space. No groundwaterencountered.




0.00-0.30

0.30-1.20

MADE GROUND: Grass over, soft brown sandy gravelly CLAY, with occasional rootlets. Gravel isangular to subrounded fine to coarse of flint and brick

MADE GROUND: Soft light brown sandy gravelly CLAY. Gravel is angular to subrounded fine tocoarse of brick and flint.

B C Legend1 of 1

STRATA

A

C

HAND PIT No

A D

SAMPLES & TESTS

BD



0

1

2

0

1

2

HAND PIT LOG


Contractor

Project ID


GENERAL REMARKS

Project

Sheet


Madigan Brown

GSI 0525


10-12-1510-12-15

HP03


Exploratory hole cleared of buriedservices. Hand pit excavated to1.20 mbgl. No groundwaterencountered.




0.00-0.38 MADE GROUND: Grass over, soft brown sandy gravelly CLAY, with occasional rootlets. Gravel isangular to subrounded fine to coarse of flint and brick

B C Legend1 of 1

STRATA

A

C

HAND PIT No

A D

SAMPLES & TESTS

BD



0

1

0

1

HAND PIT LOG


Contractor

Project ID


GENERAL REMARKS

Project

Sheet

All dimensions in metresScale 1:12.5

Madigan Brown

GSI 0525


10-12-1510-12-15

HP04


Exploratory hole cleared of buriedservices. Hand pit terminated at0.38 mbgl due to structuralstability of the foundations andthe overlying wall. Nogroundwater encountered.




APPENDIX D

HAND PIT SKETCHES AND PHOTOGRAPHS

GeoCon Site Investigations LtdSuite 8 Marple House,39 Stockport Road,MarpleStockport,SK6 6BD.Tel: 0844 504 3901, Fax: 0844 504 3902,Email: [email protected]: www.geoconsiteinvestigations.com

SITE NAME/CONTRACT


DRAWING NO.

GSI0525/03

SCALE

N.T.S

TITLE

Hand Pit HP01 Sketch and Photograph

DATE

January 2016

DRAWN BY

IW


SITE NAME/CONTRACT


DRAWING NO.

GSI0525/04

SCALE

N.T.S

TITLE


DATE

January 2016

DRAWN BY

IW


SITE NAME/CONTRACT


DRAWING NO.

GSI0525/05

SCALE

N.T.S

TITLE


DATE

January 2016

DRAWN BY

IW


SITE NAME/CONTRACT


DRAWING NO.

GSI0525/06

SCALE

N.T.S

TITLE


DATE

January 2016

DRAWN BY

IW

APPENDIX E

GEOTECHNICAL TESTING RESULTS

LaboratoryReport

GEO Site & Testing Services Ltd

Contract Number: 29464

Notes: Observations and Interpretations are outside the UKAS Accreditation* - denotes test included in laboratory scope of accreditation# - denotes test carried out by approved contractor@ - denotes non accredited tests

This certificate is issued in accordance with the accreditation requirements of the United Kingdom Accreditation Service. The results reported herein relate only to the material supplied to the laboratory. This certificate shall not be reproduced in full, without the prior written approval of the laboratory.

Approved Signatories:Alex Wynn (Associate Director) - Benjamin Sharp (Contracts Manager) - Emma Sharp (Office Manager)Paul Evans (Quality/Technical Manager) - Vaughan Edwards (Managing Director)

GEO Site & Testing Services LtdUnit 4, Heol Aur, Dafen Ind Estate, Dafen, Llanelli, Carmarthenshire SA14 8QNTel: 01554 784040 Fax: 01554 784041 [email protected] gstl.co.uk

Client's Reference: GSI 0525 PO 15/0384 Report Date: 18-01-2016

Client GeoCon Site Investigation Limited15 Belmont DriveMarple BridgeStockportEnglandSK6 5EA

Contract Title: Lexham Gardens, LondonFor the attention of: Ian Walker

Date Received: 23-12-2015Date Commenced: 23-12-2015

Date Completed: 18-01-2016

Test Description Qty

Moisture Content1377 : 1990 Part 2 : 3.2 - * UKAS

2

4 Point Liquid & Plastic Limit (LL/PL)1377 : 1990 Part 2 : 4.3 & 5.3 - * UKAS

2

PSD Wet Sieve method1377 : 1990 Part 2 : 9.2 - * UKAS

1

(GI) BRE Suite Total Sulphate, Aqueous Sulphate, Total Sulphur, Aqueous Nitrate, Aqueous Mag,Chloride,1377 : 1990 Part 3 & BRE CP2/79 - @ Non Accredited Test

2

Disposal of Samples on Project 1

Client ref: GSI 0525

Location:

Contract Number:

Hole Sample Number Number

WS01 D 2.50 Brown gravelly sandy fine to medium silty CLAY.WS01 D 3.50 Brown gravelly sandy fine to medium silty CLAY.

For and behalf of GEO Site & Testing Services Ltd

Authorised By:Emma Williams (Office Manager)

Date: 18.1.16


Type Depth (m)

Note: Results on this table are in summary format and may not meet the requirements of the relevant standards, additional information is held by the laboratory

29464-040116

Description of Sample*

GEO/005

Test Report: Method of the Determination of the plastic limit and plasticity indexBS 1377 : Part 2 : 1990 Method 5

Client ref: GSI 0525

Location:

Contract Number: 29464-040116

Hole/ Moisture Liquid Plastic Plasticity %

Sample Sample Content Limit Limit Index Passing Remarks

Number Type % % % % .425mm

Cl. 3.2 Cl. 4.3/4.4 Cl. 5. Cl. 6.

WS01 D 2.50 20 41 16 25 91 CI Intermediate PlasticityWS01 D 3.50 14 38 15 23 87 CI Intermediate Plasticity

Symbols: NP : Non Plastic # : Liquid Limit and Plastic Limit Wet Sieved


Authorised By:Emma Sharp (Office Manager)Date:

Depth

m

18.1.16


PLASTICITY CHART FOR CASAGRANDE CLASSIFICATION.

BS 5930:1999+A2:2010

0

10

20

30

40

50

60

70

80

90

0 20 40 60 80 100 120

Pla

stic

ity

Inde

x (%

)

Liquid Limit (%)

CE CH CI CV CL

ME MV MH MI ML

Unit 4Heol Aur

Dafen Ind EstateDafenCarmarthenshire

SA14 8QNTel: 01554 784040

01554 750752Fax: 01554 770529

01554 784041Web: www.geo.uk.com

Date: 14/01/2016

Client: Geocon

Our Reference: 29464-040116

Client Reference: GSI0525

Contract Title: Lexham Gardens, London

Description: (Total Samples) 2

Date Received: 04/01/2016

Date Started: 12/01/2016

Date Completed: 14/01/2016

Test Procedures: (B.S. 1377 : PART 3 : 1990 AND BRE CP2/79)

Notes:

Solid samples will be disposed 1 month and liquids 2 weeksafter the date of issue of this test certificate

Approved By:

Authorised Signatories: Emma Williams Ben Sharp Paul EvansLaboratory Office Manager Contracts Manager Quality Manager

Certificate of Analysis

of 1

Contract No:

Client Ref:Location:

Date:

Summary of Chemical Analysis(B.S. 1377 : PART 3 : 1990 AND BRE CP2/79)

Chloride ContentSoluble Ground- pH Total Magnesium Nitrate Organic

Hole Sample Depth Chloride as water Value Sulphur %Number Number m % equiv. @ 25oC % g/l mg/l

NaCl g/l

Clause 7.3 Clause 7.2 Clause 9.

WS01 4.50 0.22 ( 0.27 ) 0.01 ( 0.02 ) ncp 7.77 0.02 <1 <10WS01 5.50 0.19 ( 0.23 ) 0.01 ( 0.01 ) ncp 7.69 0.01 <1 <10

NCP - No Chloride present

Sulphateg/l

Clause 5.4.

29464-040116GSI0525

Sulphate Content SO3 (as SO4)

Ground-water

Acid


Sulphateas g/l SO4

Clause 5.5.Clause 5.5.

as % SO4

14/01/2016

AqueousExtractSoluble

GEO/104

Test Report: Particle Size Distribution TestBS 1377 Part 2:1990.Wet Sieve, Clause 9.2

Client ref: Sample Number:

Contract Number: Depth from (m): 4.70Hole Number: Depth to (m): N/A

Sample Type: DLocation: Lexham Gardens, LondonDescription:

CLAY COBBLES

BS Test %

Sieve Passing

125 10090 10075 10063 10050 100

37.5 10028 9420 8814 8610 846.3 825.0 813.35 812.00 811.18 810.60 780.425 680.300 460.212 320.150 290.063 21

Particle %Diameter Passing

0.02 # Sand Gravel Soil Fraction

0.006 #

0.002 #

Remarks:#- not determined


Authorised By:Emma Sharp (Office Manager)

Date:

GSI 052529464-040116WS01

18.1.16

Brown gravelly silty clayey fine to medium silty CLAY

Total Percentage21 60 19 0

Cobbles

Coarse

SILT SAND GRAVEL

Coarse

Silt and Clay

Fine Medium Coarse Fine MediumMediumFine

0.00

2

0.00

6

0.03

0

0.06

0

0.20

0

0.60

0

2.00

60

200

20

6.0

0

10

20

30

40

50

60

70

80

90

100

0.001 0.01 0.1 1 10 100 1000

Per

cen

tage

Pas

sin

g.

Particle Size (mm).

GEOENVIRONMENTAL SITE INVESTIGATION REPORT PHASE II ...

Documents

Transcript of GEOENVIRONMENTAL SITE INVESTIGATION REPORT PHASE II ...