geotech report · MCU15/0087

Slope Stability and Geotechnical Assessment
1 Natasha Avenue, Noosa Heads




1.       Introduction
Coffey Geotechnics Pty Ltd (Coffey) was commissioned by Ms Annette Warner to undertake a slope
stability and geotechnical assessment for the proposed residence at 1 Natasha Avenue at Noosa
Heads. A multi-level building is proposed for the site. The location of the proposed building is shown
on a site layout and contour plan (see Appendix A) provided by Ms Annette Warner.

The geotechnical slope stability assessment and associated geotechnical model are based on the
subsurface investigations and visual observations made by Coffey during field inspections of the site.

This slope stability assessment has been prepared by Coffey, a specialist geotechnical engineering
consultant with extensive experience in slope stability assessment in this area. The slope stability
has been assessed using a framework guided by a process developed by the Australian
Geomechanics Society - “A National Landslide Risk Management Framework for Australia”; Volume
42 March 2007 (AGS2007).

The aim of this study was to assess the slope stability risk of the proposed structure and adjacent
areas along with providing design parameters for foundation design.



2.       Proposed Design
The building concept design (attached in Appendix A) depicts a single storey structure across the
southern end of the site with a dual storey portion overlooking the escapement of the dune to the
north.



3.       Fieldwork
The investigation was carried out under the direction of a Principal Engineer from Coffey’s Kunda
                    th      th
Park office on the 4 and 10 of August 2015. The fieldwork comprised:

     
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         Site walkover conducted on the 4 August 2015 by a Coffey Geotechnical Engineer and a
         Principal Engineer. During this inspection, the general site conditions were observed, slopes
         measured and features relevant to the stability of the proposed building area noted.

        At the time of the site walkover, six Dynamic Cone Penetrometer (DCP) tests were
         undertaken to depths between 3.3 metres and 4.5 metres below the current surface level.

     
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         On the 10 August 2015, two boreholes were drilled to a depth of 6.0 metres below the
         current surface level immediately adjacent to the dune escarpment.

Drilling was conducted in the full time presence of a Geotechnical Engineer from Coffey’s Kunda Park
office, who logged the materials encountered. Figure 1 shows the approximate locations of the DCP
tests and boreholes. Engineering logs are presented in Appendix B together with explanation sheets
defining the terms and symbols used in their preparation. DCP test results are attached in Appendix
C.

Each borehole was reinstated upon completion by backfilling using soil cuttings up to the ground
surface level.




Coffey
GEOTKPAR02068AA/A                                                                                        1
12 August 2015