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

Project No. 1-22543                                                                                                          Page | 14
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




5.0 ENGINEERING STABILITY RECOMMENDATIONS

    5.1 General Recommendations with Respect to Construction
Continued long term stability of the site is subject to development of the site taking place in
accordance with the guidelines of this report and relevant Australian Standards and good
building practices.

Based on the field observations, published hazard mapping and observed subsurface
conditions, it is concluded that provided the proposed development is undertaken using
our recommendations, it would not adversely affect the slope stability conditions at this
site. This conclusion is qualified by the following provisions:-

          The earthworks should be designed and constructed in accordance with sound and
           proper engineering principles.
          Likewise, the future construction should be planned designed and constructed in
           accordance with sound and proper engineering principles, and more specifically in
           accordance with good hillside construction practices (refer Appendix I).
          All construction works to be carried out in accordance with the recommendations of this
           report.
          The access and drainage infrastructure must be properly and effectively maintained, to
           ensure that all stormwater is intercepted and controlled. This requirement extends to all
           owners and occupiers being aware that ongoing maintenance of the site drainage is
           essential for continued site stability.

The following recommendations should be adopted:-

          All engineering works should follow the appropriate codes i.e.:-
                       o     Earthworks - AS 3798 "Guidelines on Earthworks for Commercial and
                             Residential Developments".
                       o     Footings for buildings - AS 2870 'Residential Slabs and Footings'.
                       o     Retaining structures - AS 4678 ‘Earth Retaining Structures’.
          Vegetation - where possible, the prompt re-establishment of ground cover should be
           undertaken to reduce the risk of surface scour during and following rainfall. Where not
           possible, other forms of surface protection should be adopted.

    5.2 Stormwater Drainage
Appropriate drainage provisions are essential in any development. Adequate subsoil and
surface drainage should also be incorporated in any retaining wall construction.

Preferably, where possible, roof water should be taken via piped conduits to the road drainage
system or to water storage tanks. Any overflow from water storage tanks should be piped to the
road drainage system. Any outlet for pool backwash will also be required to be discharged into
an adequately designed system and piped to the road drainage.

Other usual treatment options associated with Good Hillside Practice, as outlined in Appendix I
should also be adopted. Some of these are implicit or assumed by the analysis. For example,
provision of surface water drainage measures (such as a lined drain across the slope uphill



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