Geotechnical Report Dec 2013 Revision 1

                             55 LAKE MACDONALD DRIVE, COOROY


        METHOD OF INVESTIGATION
4.1      Fieldwork
The subsurface investigation comprised excavation of thirteen test pits (designated TP1 to TP13) to depths of
up to 2.2 m below ground level (BGL) across the site using either a Komatsu PC220 (22 tonne) excavator or a
Komatsu PC78MR (8 tonne) excavator. The smaller excavator was used for the test pits on the eastern side
of the site (Stage 3) due to access difficulties in getting the larger excavator across the drainage gully.

Test pits TP1 to TP6 were located within proposed residential allotments. Test pits TP7 to TP9, TP12 and
TP13 were located in proposed road areas. Test pit TP10 was located in where a sewer manhole is
proposed, and test pit TP11 was excavated to assess the material near the central drainage gully for
accessibility. No deeper test pits were excavated in Stage 3, as the sewer line had been installed.

Test pits TP1 to TP4, TP7, TP8, TP12 and TP13 were located within Stage 4, with test pits TP5, TP6, TP9 to
TP11 being located in Stage 3.

Pocket penetrometer (PP) testing was carried out on the sidewalls of the test pits to gain an indication of soil
strength/consistency. Disturbed samples were taken from the test pits for laboratory soil classification testing.

In addition to the above, two hand augered boreholes (HA1 and HA2) were drilled within the western drainage
gully to depths of 1.0m BGL. Dynamic cone penetrometer (DCP) tests were carried out adjacent to the
boreholes, and also at the location of TP8 to assess the strength/consistency of the soil types within the gully
area. The hand augers were located near the widest part of the drainage gully, where it was expected that the
greatest accumulation of sediments may occur.

Test pit and borehole locations were positioned on site using offsets from the road centreline and boundary
survey pegs. Test co-ordinates were obtained using a hand held GPS with an accuracy of ±5m, and are
provided on the test pit and borehole logs.

The fieldwork was carried out in the presence of an experienced geotechnical engineer from Tectonic on 17
October 2013 (test pits) and 28 November 2013 (hand augered boreholes). Reports of test pits and boreholes
(with DCP test results), along with explanatory notes are presented in Appendix B. Test pit and borehole
locations are shown in Figure 1, and also on C&T layout drawing in Appendix A.

4.2       Laboratory Testing
Selected soil samples were dispatched to Geotech (SC) Pty Ltd, a NATA accredited geotechnical testing
laboratory located in Kawana, for geotechnical testing. Laboratory testing was undertaken in accordance with
Australian Standard AS1289 Method for Testing Soils for Engineering Purposes and comprised:

       Atterberg Limits (liquid limit, plastic limit, plasticity index, linear shrinkage) and Fines Content analyses
        for soil classification purposes; and
       Soaked CBR (single point) for pavement design purposes.

A summary of the laboratory testing results is presented in Section 5.3, and the laboratory test certificates are
attached in Appendix C.




2 December 2013
Report N0. 13008-001-Rev1                               6