RFI - Attachment C - Slope Stability Assessment and Geotechnical report · MCU20/0026

Project No. 1-22543                                                                                                          Page | 17
June, 2020
Ref: 1-22543, 2020-05-20, BR SSA VER 1
Sanya Holdings – Slope Stability Assessment and Geotechnical Report - Proposed Residence, 40 Park Crescent, Sunshine Beach




Note: The surface silty sands will cause problems with trafficability/workability should
this material be wet/become wet prior to or during construction.

Given no structural filling is a currently proposed, no further specific earthworks
recommendation will be provided. The author can be contacted if further information is required.

           6.1.3       Batters

It is understood that all cuts will be supported by temporary and later permanent retaining walls
with no requirements currently for batters on the site. Should batter angles be required, please
contact to author to discuss their use.

    6.2 Building Foundations

           6.2.1       General

Given the subsurface profile encountered, the expected loads and likely excavation depths, a
high level strip and pad footing system may be possible to be adopted for the proposed
basement section (only) at the south western end of the development, provided all footings are
founded into at least medium dense sand and the presence of loose sand is taken into account.

Deep foundations would be required outside of the basement cut area to reach at least the
medium dense sands (i.e. up to approx. 2.5m below existing down slope surface levels) and
could also be adopted as an alternative foundation system across the entire site and/or for
retention systems.

           6.2.2       Site Classification as per AS 2870-2011

General

A site classification, in accordance with AS 2870 'Residential Slabs and Footings' (it is
recommended that the reader satisfy themselves that the use of AS 2870 is applicable for the
proposed design) has been carried out with the following information:-

          Subsurface profile:
                      Possible minor fill
                      Natural sand soils
          Proposed earthworks:
                      Cuts of up to approx. 4.0m to 5.0m with backfilling up to approx. 3.5m.
          Soil Moisture Model:
                      A zone of moisture variation of 1.8m
                      A crack zone of 0.9m
                      pF = 1.2

Site Classification

According to AS 2870-2011, the site has been designated Class 'P' due to:-

          The potential presence of uncontrolled fill in excess of 0.4m in depth as defined in AS
           2870-2011 Clause 2.5.3;


                                                                                                               SOIL SURVEYS