Geotechnical Investigation Report

J001369-001-R-Rev0                                                                                August 2021




                        Brick retaining wall




     Timber sleeper retaining wall




Photograph 3: View looking approximately north-west towards the existing retaining walls (3 August 2021).

4.0      INVESTIGATION
The investigation included the following:

 ▪     A review of geological and landslide hazard overlay plans

 ▪      Walk-over survey and subsurface investigation and sampling at two locations

4.1     Fieldwork
A walkover survey was carried out by a geotechnical engineer to map topographical and surface features,
such as slope angles, signs of slope instability and groundwater seepage.
Following the walkover, a subsurface investigation was undertaken, which comprised the drilling of two
boreholes (designated HA1 and HA2) to 4 m below ground level (BGL). Due to site access constraints, the
boreholes were drilled using hand augering techniques. Dynamic cone penetrometer (DCP) testing was
undertaken adjacent to the boreholes to assess soil density/consistency. Soil samples were also collected
from the boreholes.
Borehole positions were recorded in the field using a handheld GPS unit.
The test locations are shown on the attached Figure 1. Reports of Boreholes are attached in Appendix A,
together with explanatory notes. The subsurface conditions are discussed in Section 5.2.
The fieldwork was carried out on 3 August 2021 by a geotechnical engineer from Core who logged
subsurface conditions in accordance with AS1726-2017 Geotechnical site investigations and undertook the
field testing and sampling.




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