Reference Document - Geotech Report - MCU24 0094 · MCU24/0094

                             PROPOSED RESIDENCE
                             33 ROSS CRESCENT, SUNSHINE BEACH

3.0      METHOD OF INVESTIGATION
3.1      Fieldwork
An experienced geotechnical engineer from Tectonic undertook a site walk-over on 3 April 2024 to visually
assess indicators of past slope instability. The walk-over included assessment of soil exposures, surface
drainage conditions, topography, evidence of erosion or past instability, and vegetation coverage/condition.
In conjunction with the walk-over three hand auger boreholes (designated BH1 to BH3) were drilled.
Boreholes BH1 and BH2 were drilled within the proposed building footprint, and BH3 further downslope
towards the toe of the main high dune. In situ testing utilising the dynamic cone penetrometer (DCP) method
was completed from surface adjacent to each borehole, and at selected depths downhole. In addition, three
standalone DCP tests were also conducted at northern and southern points along the eastern boundary, and
around half-way down the dune face. Hand augers were taken to slow progress at depths of between 3 m
and 4 m below ground level (BGL) due to collapsing sands, with DCP testing extending below the base of
the boreholes to depths of up to 5.5 m BGL.
Boreholes were backfilled with drilling spoil and left slightly mounded at the ground surface. Disturbed soil
samples were recovered from the auger cuttings. The engineer was responsible for logging soil profiles and
maintaining investigation practices in accordance with AS1726 Geotechnical site investigations, supervising
in situ testing, and recovering samples.
Borehole and DCP reports are attached in Appendix A, together with explanatory notes. Test locations are
shown in Figure 1 and subsurface conditions are discussed in Section 4.4.

3.2      Geotechnical Laboratory Testing
Two selected disturbed soil sample were dispatched to Construction Sciences, a NATA accredited laboratory
located in Kunda Park, for geotechnical testing. Testing comprised two particle size distribution (PSD) tests
for soil classification purposes. Geotechnical laboratory testing was undertaken in accordance with
Australian Standard AS1289 Method for Testing Soils for Engineering Purposes.
Laboratory test results are summarised in Section 4.6, and the test certificates are attached in Appendix B.




18 June 2024
Report No. 24096-001-Rev0                             3