Attachment 12 - Geotechnical Investigation Report

                             PROPOSED RETIREMENT DEVELOPMENT
                             MYALL STREET, COOROY

4.0      METHOD OF INVESTIGATION
4.1      Fieldwork
13 boreholes (designated BH1 to BH13) were drilled using a 4WD mounted drilling rig owned and operated
by Ground Drill, mostly to a target depth of 3 m below ground level (BGL). Borehole drilling refusal was
encountered in borehole BH13 only, to the south-west of the site, on possible weathered rock at 2.3 m BGL.
Boreholes were spread across the site area to give a general representation of the site conditions across
the proposed development areas. The original project brief indicated that the proposed clubhouse would be
in the north of the site (Ref. Jared Poole Design Dwg. No. BP1074/SK1.01, Issue C, dated January 2019)
and hence deeper drilling to 6 m BGL was undertaken in that vicinity. Similarly at the time of commissioning
the investigation, a two lane driveway was not proposed along the northern boundary; and neither were
such significant earthworks anticipated (thus the majority of boreholes being terminated at 3 m BGL).

In situ testing comprised dynamic cone penetrometer (DCP) tests adjacent to all locations, and at selected
intervals within all boreholes. Pocket penetrometer (PP) testing was carried out on clay samples recovered
from the augers, and on undisturbed (U50) tube samples.

Disturbed and undisturbed soil samples were taken from the boreholes for laboratory testing. Boreholes
were typically drilled using a 100 mm diameter solid flight auger. Four bulk disturbed samples from the likely
pavement subgrade materials were recovered for California Bearing Ratio (CBR) testing, using a 300 mm
diameter auger.

Fieldwork was undertaken in the presence of an experienced engineering geologist from Tectonic between
on 10 April 2018. The geologist was responsible for logging soil profiles in accordance with AS1726
Geotechnical site investigations, making groundwater observations, and recovering soil samples. All
boreholes were backfilled with auger cuttings on completion, with excess spoil slightly mounded at the
surface. The borehole drilling was combined with a site walkover survey including observations of soil and
rock exposures, surface drainage conditions, topography, evidence of erosion, and vegetation
coverage/condition.

Borehole reports are attached in Appendix A, together with explanatory notes. Borehole locations are
shown on Figure 1, attached at the end of this report.

4.2      Laboratory Testing
Undisturbed and disturbed soil samples were dispatched to SMEC Pty Ltd, a NATA accredited geotechnical
laboratory located in Birtinya, for geotechnical testing. Laboratory testing was undertaken in accordance
with Australian Standard AS1289 Method for Testing Soils for Engineering Purposes and comprised:

       Three Shrink Swell Index (SSI) to enable estimation of characteristic ground surface movements;
       One Atterberg Limits and Percent Fines for soil classification purposes;
       Three CBR tests to enable an assessment of pavement design parameters.
Geotechnical laboratory results are discussed in Section 5.3. The geotechnical laboratory certificates are
attached in Appendix B.




17 May 2019
Report No. 19071-001-Rev0                              5