Project No: 2014-251, December 2014

G C CROZIER - Geotechnical Consultants Engineering Geologists & Geotechnical Engineers

Crozier Geotechnical Consultants ABN: 96 113 453 624

Unit 12/ 42-46 Wattle Road Phone: (02) 9939 1882

Brookvale NSW 2100 Fax : (02) 9939 1883 Crozier Geotechnical Consultants is a division of PJC Geo-Engineering Pty Ltd

Date: 2nd December 2014

No. Pages: 1 of 4

Project No.: 2014-251

GEOTECHNICAL REPORT FOR PROPOSED SWIMMING POOL AND ALTERATIONS

2 FREEMAN PLACE, CONCORD.

1. INTRODUCTION:

This report details the results of a geotechnical investigation into acid sulfate soils carried out for proposed

alterations and additions at 2 Freeman Place, Concord, NSW. The investigation was undertaken by Crozier

Geotechnical at the request of the client Mr Roy Hraiki.

For the purpose of this report the front boundary, adjacent to Freeman Place is considered the northern

boundary. The site is situated on the high, southern side of the Freeman Place cul-de-sac within gently

sloping topography. The site contains a relatively new two storey rendered house on the centre of the block

with lawns, gardens and paved area surrounds. It is understood that a new in-ground swimming pool is

proposed along the eastern side of the existing house. The pool will require an excavation of up to 1.5m

depth below existing ground surface levels. Minor landscaping alterations are also proposed.

The site is located within the precinct of the City of Canada Bay Council. A review of the Councils LEP 2013,

identified that the site is located within land classified as Class 5 (Sheet ASS 004) and is within approximately

20m of land classified as Class 2 Acid Sulfate Soils.

For Class 5 land the LEP 2013 states that all developments must be assessed where - Works within 500 metres of

adjacent Class 1, 2, 3 or 4 land that is below 5 metres Australian Height Datum by which the water table is likely

to be lowered below 1 metre Australian Height Datum on adjacent Class 1, 2, 3 or 4 land. Due to the proposed

excavation an investigation into site conditions was required.

The geotechnical investigation comprised:

• A detailed geotechnical inspection of the site and adjacent land by a Geotechnical Engineer

including a photographic record of site conditions.

• Drilling of a hand auger borehole to investigate subsurface geology. Dynamic Penetrometer

testing was also undertaken adjacent to the hand auger location.

• Soil samples were collected from the borehole for assessment of acid sulfate attributes whilst the

borehole was inspected for the presence of a water table.

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Project No: 2014-251 Concord 2014

CROZIER - Geotechnical Consultants Engineering Geologists & Geotechnical Engineers G C

The following plans and diagrams were supplied for this work;

• Landscape Design by Jacqui Ray, Project: Proposed Swimming Pool and Surrounds, Drawing No.

1 of 2, Revision: C, Dated: 29/10/14.

• Site Survey Plan by C & A Surveyors, Reference: 1880-14 DET_2, Date Drawn: 28-10-2014.

2. SITE FEATURES:

2.1. Description:

The site is situated on the high southern side of the street, adjacent to the cul-de-sac. It is within gently

sloping topography close to the base, on the northern side, of a low north-east striking ridge that extends

into Hen and Chicken Bay to the east. Directly across the road from the site are open grass fields for a golf

course (Massey Park Golf Club). These fields are gently sloping to near level and occupy the valley floor to

the north-west of the site.

The site contains a two storey rendered house on the southern side of the block with a level, stenciled

concrete driveway providing access to an open carport on the front south-western corner of the house. The

remainder of the front yard is formed with garden beds and lawn which then extends around the eastern

side of the house to the mid-point of the structure. Extending from this point and continuing around the

entire rear of the house is a level paved terrace with a narrow raised garden bed along the rear boundary.

A review of the survey drawing identified that the site is near level with ground surfaces between R.L. 3.27

and R.L. 3.89.

2.2. Geology:

Reference to the Sydney 1: 100,000 Geological Series sheet (9130) indicates that the site is underlain by

Hawkesbury Sandstone (Rh) which is of Triassic age. However it is close to an area containing man-made

fill (Mf) which has been used to infill the valley to the north over the natural sediments (Qha) of

Quaternary age. The Hawkesbury Sandstone bedrock typically comprises medium to coarse grained quartz

sandstone with minor lenses of shale and laminite whilst the Quaternary sediments consist of silty to peaty

quartz sand, silt and clay. The man-made fill is expected to comprise dredged estuarine sand and mud with

demolition rubble.

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Project No: 2014-251 Concord 2014

CROZIER - Geotechnical Consultants Engineering Geologists & Geotechnical Engineers G C

3. FIELD WORK

3.1 Methods:

The field investigation comprised a walk over inspection of the site and adjacent properties on the 26th

November 2014 by a Geotechnical Engineer. It involved a photographic record of site conditions as well as

geological/geomorphological inspection of the site and adjacent land. It also included the drilling of one

hand auger borehole (BH1) to investigate sub-surface geology and collect samples for Acid Sulfate Soils

analysis.

Dynamic Cone Penetrometer testing was carried out adjacent to the borehole, in accordance with

AS1289.6.3.2 ! 1997, "Determination of the penetration resistance of a soil ! 9kg dynamic cone

penetrometer# to estimate near surface soil conditions and confirm depths to bedrock. Mapping information

and test locations are shown on Figure: 1, Appendix: 2 along with detailed log sheets. Explanatory notes

are included in Appendix: 1.

3.2. Boreholes:

Borehole 1 (BH1) was drilled through the lawn area on the eastern side of the house, in the location of the

proposed swimming pool. The borehole intersected dark brown, sandy topsoil fill and light yellow-brown,

sandy fill to 0.30m depth. Light yellow-orange fine grained moist sand with some clay was intersected

between 0.30m and 0.78m depth before medium grained, sandy clay with sandstone gravel was

encountered. At 1.10m depth light grey and orange, medium grained, extremely weathered, extremely low

strength sandstone was encountered. At 1.20m depth the hand auger refused on extremely weathered

sandstone.

DCP 1 was undertaken adjacent to the borehole whilst DCP 1a was undertaken from the base of the

borehole upon completion. The test results suggest the fill is very dense with loose to medium dense sands

then stiff sandy clay. DCP 1a refused on solid material at 1.50m depth suggesting sandstone of at least very

low strength.

The borehole was left open for 0.25hrs upon completion, at which time there were no signs of a

freestanding ground water table or significant groundwater seepage in the borehole.

Soil samples were collected at 0.45m, 0.85m 1.10m and 1.20m depth from the borehole. All samples were

placed inside clean glass laboratory sample jar immediately following drilling.

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Project No: 2014-251 Concord 2014

CROZIER - Geotechnical Consultants Engineering Geologists & Geotechnical Engineers G C

4. COMMENTS:

4.1. Geotechnical Assessment:

The site investigation identified minor fill soil over natural sand and sandy clay soils which are considered

to be residual and derived from the weathering of sandstone bedrock. Sandstone of extremely low strength

was encountered at 1.10m depth with very low to low strength sandstone at around 1.50m depth. There

were no signs of a groundwater table to 1.20m depth within the borehole or within the DCP test hole to

1.50m depth upon completion.

Detailed geological logging of the soils samples identified that the soils and weathered bedrock below the

site do not contain any indicators of acid or potential acid sulfate soils. The proposed works involve an

excavation that will extend to approximately 1.50m depth however the site testing confirmed that a water

table is not expected within this depth of excavation. As such the works will not require dewatering other

than for minor potential seepage and will not involve a lowering of the groundwater table below 1m AHD

on the adjacent Class 2 land.

Therefore the proposed works do not require the preparation of an Acid Sulfate Soils Management Plan and

no further testing or reporting is required as part of this Development Application.

The client and builder should consider and prevent any potential undermining of the sites existing house

and the neighbouring property to the north during excavation. Should further geotechnical detail or advice

on this be required please don$t hesitate to contact the undersigned.

Troy Crozier

Principal Engineering Geologist

MEng.Sc. BSc. MAIG

5.0. REFERENCES:

1. C. W. Fetter 1995, "Applied Hydrology# by Prentice Hall.

2. Acid Sulfate Soil Manual, New South Wales Acid Sulfate Soil Management Advisory Committee,

August 1998.

3. City of Canada Bay Council LEP 2013

CLIENT: DATE: 26/11/2014 BORE No.: 1

PROJECT: PROJECT No.: 2014-251 SHEET: 1 of 1

LOCATION: SURFACE LEVEL: RL: 3.70m

Depth (m)PRIMARY SOIL - strength/density, colour, grainsize/plasticity,

moisture, soil type incl. secondary constituents, Type Depth (m) Type0.00 other remarks

LAWNTOPSOIL (FILL) - Dark brown, fine to medium grained, moist,

sand fill with some ironstone gravel.0.22

SAND (FILL) - Light yellow brown, medium grained, moist, sand fillwith trace of clay.

0.30SAND - Light yellow-orange , fine grained, moist, sand with some clay,

occasional sandstone gravel. D 0.45

0.78SANDY CLAY - Light orange-yellow, medium plasticity, moist, medium D 0.85

grained sandy clay with some red mottling and sandstone gravel.

1.00

1.10 D 1.10EXTREMELY WEATHERED SANDSTONE - Light grey and orange,

medium grained, moist, some gravel, minor clay content. D 1.201.20

HAND AUGER REFUSAL at 1.20m depth on extremely weathered, Extremely low strength, sandstone bedrock.

2.00

RIG: None DRILLER: KB LOGGED: AW

METHOD: Hand Auger

GROUND WATER OBSERVATIONS: No groundwater table or seepage identified

REMARKS: CHECKED: TMC

2 Freeman Place, Concord.Alterations.

Results

TEST BORE REPORT

Description of Strata Sampling In Situ Testing

Mr. Roy Hraiki.

New Swimming Pool and Minor

Crozier Geotechnical Consultants

CLIENT: DATE: 26/11/2014

PROJECT: New Swimming Pool and Alterations. PROJECT No.: 2014-251

LOCATION: SHEET: 1 of 1

Depth (m)

TEST METHOD: AS 1289. F3.2, CONE PENETROMETER

REMARKS: (B) Test hammer bouncing upon refusal on solid object -- No test undertaken at this level due to prior excavation of soils

2.40 - 2.55

2.55 - 2.70

2.70 - 2.85

2.85 - 3.00

1.50 - 1.65

1.65 - 1.80

1.80 - 1.95

1.95 - 2.10

2.10 - 2.25

2.25 - 2.40

0.60 - 0.75

0.75 - 0.90

0.90 - 1.05

1.05 - 1.20

1.20 - 1.35

1.35 - 1.50

DCP1

0.00 - 0.15

0.15 - 0.30

0.30 - 0.45

0.45 - 0.60 5

12

DCP1a

DYNAMIC PENETROMETER TEST SHEET

15 ref. @ 1.5m depth

(B)

13 _

4

3 _

5 _

2 _

_

_

18 _

Mr. Roy Hraiki.

Test Location

2 Freeman Place, Concord.

5 _