GEOTECHNICAL INVESTIGATION KAWAINUI MARSH …

GEOTECHNICAL INVESTIGATION KAWAINUI MARSH RESTORATION OF ENDANGERED HABITATS & WETLANDS KAHANAIKI SITE ACCESS ROAD KAILUA, OAHU, HAWAII DLNR JOB NO. D00CO44A

for

AECOM HIRATA & ASSOCIATES, INC. W.O. 19-6200 December 6, 2019

Hirata & Associates, Inc. W.O. 19-6200

TABLE OF CONTENTS

INTRODUCTION .....................................................................................................1

PROJECT CONSIDERATIONS ...............................................................................2 SITE CONDITIONS ..................................................................................................2 SOIL CONDITIONS .................................................................................................2 CONCLUSIONS AND RECOMMENDATIONS ....................................................3 Pavement Design ...........................................................................................3 Site Grading ...................................................................................................4 ADDITIONAL SERVICES .......................................................................................5 LIMITATIONS ..........................................................................................................6

Hirata & Associates, Inc. W.O. 19-6200

APPENDICES

APPENDIX A Description of Field Investigation ................................................ Plates A1.1 and A1.2 Location Map ................................................................................ Plate A2.1 Boring Location Plan .................................................................... Plate A2.2 Boring Log Legend ....................................................................... Plate A3.1 Unified Soil Classification System ............................................... Plate A3.2 Boring Logs .................................................................................. Plates A4.1 through A4.4 APPENDIX B Description of Laboratory Testing ................................................ Plates B1.1 and B1.2 Consolidation Test Reports ........................................................... Plates B2.1 and B2.2 Modified Proctor Test Reports ...................................................... Plates B3.1 and B3.2 CBR Stress Penetration Test Reports ........................................... Plates B4.1 and B4.2

December 6, 2019 W.O. 19-6200

Hirata & Associates, Inc. Page 1

GEOTECHNICAL INVESTIGATION KAWAINUI MARSH RESTORATION OF

ENDANGERED HABITATS & WETLANDS KAHANAIKI SITE ACCESS ROAD

KAILUA, OAHU, HAWAII DLNR JOB NO. D00CO44A

INTRODUCTION

This report presents the results of our geotechnical investigation performed for the

proposed improvements to the Kahanaiki Site access road on the north side of

Kawainui Marsh. Our scope of services for this study included the following:

• A visual reconnaissance of the site and its vicinity to observe existing conditions which may affect the project. The general location of the project site is shown on the enclosed Location Map, Plate A2.1.

• A review of available in-house soils information pertinent to the site and

the proposed project. • Drilling and sampling four exploratory borings to depths of about 10.5

feet. A description of our field investigation is summarized on Plates A1.1 and A1.2. The approximate exploratory boring locations are shown on the enclosed Boring Location Plan, Plate A2.2, and the soils encountered in the borings are described on the Boring Logs, Plates A4.1 through A4.4.

• Laboratory testing of selected soil samples. Testing procedures are

presented in the Description of Laboratory Testing, Plates B1.1 and B1.2. Test results are presented on the Boring Logs (Plates A4.1 through A4.4), the Unified Soil Classification System (Plate A3.2), Consolidation Test reports, (Plates B2.1 and B2.1), Modified Proctor Test reports (Plates B3.1 and B3.2), and CBR Stress Penetration Test reports (Plates B4.1and B4.2).

• Engineering analyses of the field and laboratory data. • Preparation of this report presenting geotechnical recommendations for the

design of flexible and rigid pavement, gravel roads, subgrade requirements for use of geoblock and geopave support systems, and site grading.

December 6, 2019 W.O. 19-6200

Hirata & Associates, Inc. Page 2 PROJECT CONSIDERATIONS

Information regarding the proposed project was provided by your office.

The project will consist of improvements to the Kahanaiki Site access road from

Kapaa Quarry Road. The new maintenance road will include a large staging area

near the entrance, having plan dimensions of about 100 by 87 feet, then extending

for a length of about 330 feet in a northerly direction. Another staging area is

proposed at the end of the access road having plan dimensions of about 30 by 40

feet.

The proposed access road will include two steeper sections. The first section will

be approximately 28 feet in length with a proposed grade of 43 percent. The

second section will include a length of about 90 feet with a 12 percent grade.

Several roadway surfaces are being considered including gravel roads, flexible

and rigid pavements, and the use of porous pavement such as geoblock and

geopave support systems.

SITE CONDITIONS

The proposed Kawainui Marsh Kahanaiki Site access road is located across from

the entrance to the Le Jardin Academy. The proposed roadway alignment is

heavily overgrown with trees and shrubs. The site generally slopes from Kapaa

Quarry Road with elevations ranging from about +67 to +58, where the first

staging area is proposed, to an elevation of about +50 where the second staging

area is located.

SOIL CONDITIONS

All borings encountered a mottled reddish brown to brown clayey silt in a

medium stiff to stiff condition from the surface down to the maximum depths

drilled of about 10.5 feet. The clayey silt was mixed with sand and was in a moist

condition. Neither groundwater nor seepage water was encountered.

December 6, 2019 W.O. 19-6200

Hirata & Associates, Inc. Page 3 CONCLUSIONS AND RECOMMENDATIONS

Based on the results of our exploratory borings and laboratory testing, we believe,

that from a geotechnical viewpoint, the proposed Kahanaiki Site access road can

generally be developed as planned. We assume that between 0 to 5 heavy trucks

will utilize the access road daily.

Pavement Design

The following sections may be used in the design of the various pavement

sections being considered.

Gravel Road

5.5” Gravel Layer

The following gradation requirements is recommended for gravel roads. 100% passing ¾” 50 -78% passing No.4 13 – 35% passing No. 40 4 – 15% passing No. 200 Plasticity Index 4 - 12

Flexible Pavement

2” Asphalt Concrete 3” Asphalt Treated Base 6” Base Course (CBR = 85 minimum

11” Total Thickness

Rigid Pavement

6” Portland Cement Concrete 6" Base Course (CBR = 85 minimum)

12” Total Thickness

Geoblock Porous Pavement System (for H/HS-15 loading)

4” Base Course (CBR = 85 minimum)

December 6, 2019 W.O. 19-6200


Geopave Porous Pavement System (for H/HS-10 loading)

2” Base Course

Utilize high strength non-woven geotextile fabric for slopes greater than 7 to 10

percent.

Site Grading Slope Gradients - All cut and fill slopes should be stable at slope gradients of

2H:1V or flatter. In the event that cut and fill slopes exceed 15 feet in height, the

slopes should include benches at least 8 feet in width. The benches should be

constructed at intervals not exceeding 15 feet in vertical height. All slopes should

be planted as soon as practical upon completion of grading to reduce the effects of

erosion and weathering.

Fill slopes should be constructed from the bottom up. The fill should be

continually benched into existing slopes as the fill is brought up in lifts. The

benches should extend into competent material and be wide enough for

compaction equipment to work effectively. Fill slopes should be constructed by

overfilling and cutting back to the design slope gradient to obtain a well-

compacted slope face.

Site Preparation - The project site should be cleared of all vegetation and other

deleterious material. In areas requiring fill placement, the exposed subgrade

should be scarified to a minimum depth of 6 inches, and compacted to a minimum

95 percent compaction as determined by ASTM D 1557.

Temporary cuts into the onsite soils should be stable at gradients from 1H:1V or

flatter. However, it should be the Contractor's responsibility to conform to all

OSHA safety standards for excavations.

December 6, 2019 W.O. 19-6200


Onsite Fill Material - The onsite soils may be reused in compacted fills and

backfills, provided all rock fragments larger than 3 inches in maximum dimension

are removed.

As a precautionary measure, the moisture content of the clayey silt should be

maintained at about 2 percent above the optimum moisture content during

recompaction.

Imported Fill Material - Imported structural fill should be well-graded, non-

expansive granular material. Specifications for imported granular structural fill

should indicate a maximum particle size of 3 inches, and state that between 8 and

20 percent of soil by weight shall pass the #200 sieve. In addition, the plasticity

index (P.I.) of that portion of the soil passing the #40 sieve shall not be greater

than 10. Imported structural fill should have a CBR expansion value no greater

than 1.0 percent and a minimum CBR value of 15 percent, when tested in

accordance with ASTM D 1883.

Compaction - Imported structural fill and onsite soils should be placed in

horizontal lifts restricted to eight inches in loose thickness and compacted to a

minimum 95 percent compaction as determined by ASTM D 1557.

Fill placed in areas which slope steeper than 5H:1V should be continually keyed

and benched as the fill is brought up in lifts.

Backfill over Drainage Culverts – Above the crushed rock section and up to

finish subgrade elevation, the onsite soils, imported granular fill, or soils

conforming to Section 16 of the Standard Specification for Public Works

Construction for the City and County of Honolulu may be used. Backfill should

be placed in level lifts limited to 8 inches in loose thickness. Backfill material

placed above the crushed rock section up to a depth of 3 feet below finish

subgrade should be compacted to a minimum 90 percent compaction as

determined by ASTM D 1557. Within 3 feet of finish subgrade, backfill material

December 6, 2019 W.O. 19-6200


should be compacted to a minimum 95 percent compaction as determined by

ASTM D 1557.

ADDITIONAL SERVICES

We recommend that we perform a general review of the final design plans and

specifications. This will allow us to verify that the pavement design and site

grading recommendations have been properly interpreted and implemented in the

design plans and construction specifications.

For continuity, we recommend that we be retained during construction to (1)

review and/or perform laboratory testing on import borrow to determine its

acceptability for use in compacted fills, (3) observe structural fill placement and

perform compaction testing, and (4) provide geotechnical consultation as

required.

Our services during construction will allow us to verify that our recommendations

are properly interpreted and included in construction, and if necessary, to make

modifications to those recommendations, thereby reducing construction delays in

the event subsurface conditions differ from those anticipated.

LIMITATIONS

The boring logs indicate the approximate subsurface soil conditions encountered

only at those times and locations where our borings were made, and may not

represent conditions at other times and locations.

This report was prepared specifically for AECOM and their sub-consultants for

design of the proposed improvements to the Kahanaiki Site access road for the

Kawainui Marsh project. The boring logs, laboratory test results, and

recommendations presented in this report are for design purposes only, and are

not intended for use in developing cost estimates by the contractor.

APPENDIX A

FIELD INVESTIGATION

December 6, 2019 W.O. 19-6200

Hirata & Associates, Inc. Plate A1.1

DESCRIPTION OF FIELD INVESTIGATION GENERAL

The site was explored on September 26, 2019, by performing a visual

reconnaissance of the site and drilling four exploratory borings to maximum

depths of about 10.5 feet with a RAD track-mounted drill rig.

During drilling operations, the soils were continuously logged by our field

engineer and classified by visual examination in accordance with the Unified Soil

Classification System. The boring logs indicate the depths at which the soils or

their characteristics change, although the change could actually be gradual. If the

change occurred between sample locations, the depth was interpreted based on

field observations. Classifications and sampling intervals are shown on the boring

logs. A Boring Log Legend is presented on Plate A3.1, while the Unified Soil

Classification System is shown on Plate A3.2. The soils encountered are logged

on Plates A4.1 through A4.4.

Boring locations were selected by and staked out in the field by AECOM

personnel. Surface elevations at boring locations were estimated based on the

Topographic Survey Map provided by AECOM. The accuracy of the boring

locations shown on Plate A2.2 and the boring elevations shown on Plates A4.1

through A4.3 are therefore approximate, in accordance with the field methods

used.

SOIL SAMPLING Representative soil samples were recovered from the borings for selected

laboratory testing and analyses. Representative samples were recovered by

driving a 3-inch O.D. split tube sampler a total of 18 inches with a 140-pound

hammer dropped from a height of 30 inches. The number of blows required to

drive the samplers the final 12 inches are recorded at the appropriate depths on the

boring logs, unless noted otherwise. Bulk soil samples were recovered from

December 6, 2019 W.O. 19-6200

Hirata & Associates, Inc. Plate A1.2

boring B3 at a depth of about 0.5 to 3 feet below grade, and from boring B4 at

depths of about 0.5 to 2 feet.

Reference: Bryan's Sectional Maps, 2008 Edition(Copyright J.R. Clere, used with permission)

PlateA2.1

Kawainui Marsh Restoration - Kahanaiki Site

W.O. 19-6200

Geotechnical Engineering

HIRATA & ASSOCIATES, INC.

LOCATION MAP

AutoCAD SHX Text

PROJECT SITE

Approximate location of borings

LEGEND:

1" = 40'

GRAPHIC SCALE:200 FT.8040

W.O. 19-6200


BORING LOCATION PLAN A2.2


Geotechnical EngineeringPlate


W.O. 19-6200

Inorganic silts, micaceous or diatomaceous finesandy or silty soils, elastic silts.

Peat and other highly organic silts.

MAJOR DIVISIONS

GM

CORAL

Poorly graded gravels or gravel-sand mixtures, littleor no fines.

Silty gravels, gravel-sand-silt mixtures.

Clayey gravels, gravel-sand-clay mixtures.

MH

CH

HIGHLY ORGANIC SOILS

FORMATIONS

Inorganic clays of high plasticity, lean clays.

Core Sample

OH

FRESH TO MODERATELY WEATHERED BASALT

Well graded gravels, gravel-sand mixtures, little orno fines.

Inorganic clays of high plasticity, fat clays.

COARSEGRAINED

SOILS(More than50% of thematerial is

LARGER thanNo. 200

sieve size.)

FINEGRAINED

SOILS(More than50% of thematerial is

SMALLER thanNo. 200

sieve size.)

SANDS(More than

50% ofcoarse

fraction isSMALLERthan the

No. 4sieve size.)

GRAVELS(More than

50% ofcoarse

fraction isLARGER than

the No. 4sieve size.)

CLEANGRAVELS(Little or no

fines.)

CLEANSANDS

(Little or nofines.)

SANDSWITH FINES(Appreciableamt. of fines.)

SILTS AND CLAYS(Liquid limit LESS than 50.)

SILTS AND CLAYS(Liquid limit GREATER

than 50.)

GW

GP

VOLCANIC TUFF / HIGHLY TO COMPLETELYWEATHERED BASALT

Well graded sands, gravelly sands, little or no fines.

Poorly graded sands or gravelly sands, little or nofines.

Silty sands, sand-silt mixtures.

Clayey sands, sand-clay mixtures.

TYPICAL NAMESGROUPDIVISIONS

PT

GC

SW

SP

SM

SC

ML

CL

OL

SAMPLE DEFINITION

PlateBORING LOG LEGEND

GRAVELSWITH FINES(Appreciableamt. of fines.)

3" O.D. Split Tube Sampler

2" O.D. Standard Split Spoon Sampler RQD: Rock Quality DesignationShelby Tube

Organic silts and organic silty clays of low plasticity.

Organic clays of medium to high plasticity, organicsilts.

Water Table

Inorganic silts and very fine sands, rock flour, silty orclayey fine sands or clayey silts with slight plasticity.

A3.1Geotechnical Engineering


0

10

20

30

40

50

60

0 20 40 60 80 100



W.O. 19-6200


LIQUID LIMIT

ML-CL

PLASTICITY CHART

GRADATION CHART

Boulders

Cobbles

Gravel Coarse Fine Gravel

Sand Coarse Sand Medium Sand Fine Sand

Silt and Clay

Above 12 in.

3 in. to 12 in.

3 in. to No. 4 (4.76 mm)3 in. to 3/4 in.3/4 in. to No. 4 (4.76 mm)

No. 4 (4.76 mm) to No. 200 (0.074mm)No. 4 (4.76 mm) to No. 10 (2.0 mm)No. 10 (2.0 mm) to No. 40 (0.42 mm)No. 40 (0.42 mm) to No. 200 (0.074 mm)

Smaller than No. 200 (0.074 mm)

COMPONENT SIZE RANGE

COMPONENT DEFINITIONS BY GRADATION

PLA

ST

ICIT

Y IN

DE

X

CL A-Line

MH or OH

A3.2

CH

ML or OL

PlateUNIFIED SOIL CLASSIFICATION SYSTEM

LEGEND:

Boring B2 from 0.5 to 3 feet


25

15

16

21

98

80

83

80

21

30

27

27

Clayey SILT (MH) - Mottled reddish brown, moist, stiff,sandy

End boring at 10.5 feet.

Neither groundwater nor seepage water encountered.

59.0 ±R

QD

(%

)

BLO

WS

PE

R F

OO

T

DRIVING WT.

DE

PT

H(f

t)

DROP 9/26/19

GEOTECHNICAL ENGINEERING

9/26/19

PROJECT NAME Kawainui Marsh Restoration - Kahanaiki Site

B1

END DATE

START DATE

SURFACE ELEV.

WORK ORDER NO. 19-6200

DR

Y D

EN

SIT

Y(p

cf)

MO

IST

UR

EC

ON

TE

NT

(%

)

BORING LOG

Boring No.

30 in.

CO

RE

RE

CO

VE

RY

(%

)

SA

MP

LE

140 lb.

GR

AP

HIC

LOG

RE

MA

RK

S/

SA

MP

LE N

O.


Plate A4.1

MATERIAL DESCRIPTION

5

10

15

20

25

30

35

46

21

17

29

93

83

81

93

27

26

27

24

Consolidationtest

Clayey SILT (MH) - Mottled brown, moist, stiff, sandy



60.2 ±R

QD

(%

)

BLO

WS

PE

R F

OO

T

DRIVING WT.

DE

PT

H(f

t)

DROP 9/26/19


9/26/19


B2

END DATE

START DATE

SURFACE ELEV.


DR

Y D

EN

SIT

Y(p

cf)

MO

IST

UR

EC

ON

TE

NT

(%

)

BORING LOG

Boring No.

30 in.

CO

RE

RE

CO

VE

RY

(%

)

SA

MP

LE

140 lb.

GR

AP

HIC

LOG

RE

MA

RK

S/

SA

MP

LE N

O.


Plate A4.2


5

10

15

20

25

30

35

10

11/9"

16

31

79

58

89

90

36

30

20

29

Boulder from 3.5 to 5 feet.

Consolidationtest

Clayey SILT (MH) - Mottled brown, moist, medium stiffto stiff, sandy



50.0 ±R

QD

(%

)

BLO

WS

PE

R F

OO

T

DRIVING WT.

DE

PT

H(f

t)

DROP 9/26/19


9/26/19


B3

END DATE

START DATE

SURFACE ELEV.


DR

Y D

EN

SIT

Y(p

cf)

MO

IST

UR

EC

ON

TE

NT

(%

)

BORING LOG

Boring No.

30 in.

CO

RE

RE

CO

VE

RY

(%

)

SA

MP

LE

140 lb.

GR

AP

HIC

LOG

RE

MA

RK

S/

SA

MP

LE N

O.


Plate A4.3


5

10

15

20

25

30

35

51

32

21

13

89

73

84

74

26

30

28

36Grading to medium stiff.

Clayey SILT (MH) - Reddish brown, moist, stiff, sandy



41.0 ±R

QD

(%

)

BLO

WS

PE

R F

OO

T

DRIVING WT.

DE

PT

H(f

t)

DROP 9/26/19


9/26/19


B4

END DATE

START DATE

SURFACE ELEV.


DR

Y D

EN

SIT

Y(p

cf)

MO

IST

UR

EC

ON

TE

NT

(%

)

BORING LOG

Boring No.

30 in.

CO

RE

RE

CO

VE

RY

(%

)

SA

MP

LE

140 lb.

GR

AP

HIC

LOG

RE

MA

RK

S/

SA

MP

LE N

O.


Plate A4.4


5

10

15

20

25

30

35

APPENDIX B

LABORATORY TESTING

December 6, 2019 W.O. 19-2600

Hirata & Associates, Inc. Plate B1.1

DESCRIPTION OF LABORATORY TESTING CLASSIFICATION

Field classification was verified in the laboratory in accordance with the Unified

Soil Classification System. Laboratory classification was determined by visual

examination and Atterberg Limit tests. The final classifications are shown at the

appropriate locations on the Boring Logs, Plates A4.1 through A4.4 and on the

Unified Soil Classification System, Plate A3.2.

MOISTURE-DENSITY

Representative samples were tested for field moisture content and dry unit weight.

The dry unit weight was determined in pounds per cubic foot while the moisture

content was determined as a percentage of dry weight. Representative samples

were obtained using a 3-inch O.D. split tube sampler. Test results are shown at

the appropriate depths on the Boring Logs, Plates A4.1 through A4.4.

CONSOLIDATION Selected representative samples were tested for their consolidation characteristics.

The test samples were 2.42 inches in diameter and 1 inch high. Porous stones

were placed in contact with the top and bottom of the test samples to permit

addition and release of pore fluid. Loads were then applied in several increments

in a geometric progression, and the resulting deformations recorded at selected

time intervals. Test results are plotted on the Consolidation Test Reports, Plates

B2.1 and B2.2.

PROCTOR TEST

Modified Proctor tests were performed in general accordance with ASTM D 1557

on bulk soil samples obtained from boring B3 at depths between 0.5 to 3 feet

below grade, and from boring B4 at depths between 0.5 to 2 feet below grade.

The test is used to determine the optimum moisture content at which the soil

compacts to 100 percent dry density. Results are shown on Plates B3.1 and B3.2.

December 6, 2019 W.O. 19-2600

Hirata & Associates, Inc. Plate B1.2 CALIFORNIA BEARING RATIO TESTS

CBR tests were performed in general accordance with ASTM D 1883 on bulk

samples obtained from boring B3 at depths between 0.5 and 3 feet below grade,

and from boring B4 at depths between 0.5 and 2 feet below grade. The tests are

used to evaluate the relative quality of subgrade soils to be used in the design of

pavements and roadway support systems. Results are shown on Plates B4.1 and

B4.2.

0

1

2

3

4

5

6

7

8

9

1010 100 1,000 10,000 105

PlateB2.1

CONSOLIDATION TEST

Per

cen

t C

han

ge

in H

eig

ht

(%)

Consolidation Test Results

ASTM D2435 / D2435M - 11

FinalInitial

Soil Description:Boring No.:

MoistureContent

(%)

DryDensity

(pcf)

Depth (ft): 3Mottled brown clayey siltB2

24.7 26.2 83.4

84.0

Sample Description

Pressure (psf)


W.O. 19-6200



0

1

2

3

4

5

6

7

8

9

1010 100 1,000 10,000 105

PlateB2.2

CONSOLIDATION TEST

Per

cen

t C

han

ge

in H

eig

ht

(%)

Consolidation Test Results

ASTM D2435 / D2435M - 11

FinalInitial

Soil Description:Boring No.:

MoistureContent

(%)

DryDensity

(pcf)

Depth (ft): 1Mottled brown clayey siltB3

32.9 35.8 79.4

81.7

Sample Description

Pressure (psf)


W.O. 19-6200



70

80

90

100

110

10 20 30 40 50

Dry

Uni

t Wei

ght (

PC

F)

Description:Location:Soil Data

Test Results

%

Mottled brown clayey silt

PlateB3.1

ASTM D1557

Moisture Content (%)

Optimum Moisture Content:Maximum Dry Density: 104.5

20.5


PCF

MODIFIED PROCTOR TEST


W.O. 19-6200



80

90

100

110

10 20 30 40

Dry

Uni

t Wei

ght (

PC

F)

Description:Location:Soil Data

Test Results

%

Reddish brown clayey silt

PlateB3.2

ASTM D1557

Moisture Content (%)

Optimum Moisture Content:Maximum Dry Density: 97.5

28.0


PCF

MODIFIED PROCTOR TEST


W.O. 19-6200



0

20

40

60

80

100

120

140

160

180

0 0.10 0.20 0.30 0.40 0.50

Penetration (in)

ASTM D1883

Pen

etra

tion

Res

ista

nce

(psi

)

Soil Data

Test ResultsCBR Value:Expansion:

Location:Description:Sample Dry DensitySample Moisture Content

Boring B3 from 0.5 to 3 feetMottled brown clayey silt

PlateB4.1

4.5 % 6.4 %

21.0 % 105.9 pcf

CBR STRESS PENETRATION TEST


W.O. 19-6200



0

50

100

150

200

250

300

350

400

450

500

550

600

0 0.10 0.20 0.30 0.40 0.50

Penetration (in)

ASTM D1883

Pen

etra

tion

Res

ista

nce

(psi

)

Soil Data

Test ResultsCBR Value:Expansion:

Location:Description:Sample Dry DensitySample Moisture Content

Boring B4 from 0.5 to 2 feetReddish brown clayey silt

PlateB4.2

19.0 % 1.0 %

28.5 % 95.1 pcf

CBR STRESS PENETRATION TEST


W.O. 19-6200



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