ECM_22343520_v1_Geotechnical Investigation · 132000.200173.1

                                                     PROPOSED RENOVATIONS
                                                     2 ARAKOON CRESCENT, SUNSHINE BEACH

            5.2          Stability Assessment
            The risk assessment for this project has been carried out following AGS 2007 Practice Note Guidelines for
            Landslide Risk Management. Relative levels of risk and their implications are given in Table 1.
            Table 1: Stability Risk Levels
              Risk Level                   Example Implications(1)
                                           Unacceptable without treatment. Extensive detailed investigation and research, planning and implementation of
                      Very High Risk
              VH                           treatment options essential to reduce risk to Low; may be too expensive and not practical. Work likely to cost
                                           more than value of property.
                                           Unacceptable without treatment. Detailed investigation, planning and implementation of treatment options
              H       High Risk            required to reduce risk to Low. Work would cost a substantial sum in relation to the value of the property.


                                           May be tolerated in certain circumstances (subject to regulators’ approval) but requires investigation, planning and
                      Moderate Risk
              M                            implementation of treatment options to reduce risk to Low. Treatment options to reduce to Low risk should be
                                           implemented as soon as practicable.

                                           Usually acceptable to regulators. Where treatment has been required to reduce the risk to this level, ongoing
              L       Low Risk
                                           maintenance required.
                      Very Low Risk
              VL                           Acceptable. Manage by normal slope maintenance procedures.

              Note: (1) The implications for a particular situation are to be determined by all parties to the risk assessment and may depend on the nature of the
              property at risk; these are only given as a general guide.

            Considering the existing site conditions (Ref. Section 2), and subject to the implementation of
            recommendations given below, it is assessed that there would be a Low (L) Risk of global slope instability
            affecting the proposed development. Regulators (NC) normally require that a Very Low or Low Risk of
            landslide affecting the property must be demonstrated to enable development approval. Summarised in
            Table 2 is our qualitative assessment of landslide risk for the development site. A summary of qualitative
            terminology for use in assessing risk to property is attached (taken from AGS 2007).
            Table 2: Details of Qualitative Risk Assessment for Property (AGS 2007)
                                                                                             Assessed
              Hazard                                    Likelihood         Consequence         Risk            Comments




                                                                                                               Given the low to moderate natural gradients through
                                                                                                               the proposed building area, retention proposed and
              1: Failure through very loose to
                                                                                                               protection of eastern side of site using a shear pile wall
             loose natural sands above the
                                                          Unlikely           Medium               Low          it is considered Unlikely that a landslip in these
             foundation depth across the
                                                                                                               materials would affect the proposed development.
             building area.
                                                                                                               Given a potential Medium impact from such instability
                                                                                                               the resultant risk would be Low as per AGS 2007.




                                                                                                               The likelihood of a deep failure through the medium
                                                                                                               dense (or denser) natural sand below the proposed
              2: Deep failure through the                                                                      foundation depth is assessed as Rare due to the lack of
             medium dense (or denser) sands                 Rare              Major               Low          precedence of such movements locally, no signs of any
             below the foundation depth.                                                                       existing slope instability and a lack of groundwater.
                                                                                                               Although the consequence of such a failure would be
                                                                                                               Major, the resultant risk is Low as per AGS 2007.




             24 February 2023
             Report No. 22484-001-Rev0                                                 10
Document Set ID: 22343520
Version: 1, Version Date: 16/03/2023