Attachment 2- soil stability report · MCU14/0017

                                                                                       Report No. 13N 682




Table 4 – Qualitative Risk Assessment for Property
POTENTIAL                                              Assessed
HAZARD                    Likelihood   Consequence       Risk     Comment

                                                                    The likelihood of this outcome is assessed as
                                                                     Unlikely due to the predominant subsurface
                                                                        conditions and the relative absence of
                                                                     groundwater likely due to the free draining
Shallow failure in                                                nature of the subsurface soils. A consequence of
surface soils above the   Unlikely     Insignificant   Very Low   Insignificant has been assigned as the impact of
foundation zone                                                       this on the recommended steel reinforced
                                                                  concrete bored piles will be negligible due to the
                                                                      founding into dense silty sand at depth. In
                                                                  accordance with AGS 2007 the assessed risk is
                                                                                 therefore Very Low.




                                                                  The likelihood of failure through the dense sand
                                                                      is assessed as Rare due to the estimated
                                                                  strength parameters of the material assessed by
                                                                  in-situ testing and the free draining nature fot he
Deep failure through
                                                                     material. A consequence of Major has been
weathered rock below
the base of piled
                          Rare         Major             Low       assigned as the impact of this type of failure on
                                                                        the proposed residence and potentially
foundations
                                                                  surrounding residences could require significant
                                                                   stabilization and repair works at a cost close to
                                                                    the value of the property. In accordance with
                                                                   AGS 2007 the assessed risk is therefore Low.




An explanation of the terminology adopted from “Practice Note Guidelines for Landslide Risk
Management” AGS 2007 and utilized in the tables above has been provided as an attachment to
this report.



5.       CONCLUSIONS



As a general rule, regulators such as Sunshine Coast Council require that developments are
assessed as having a Very Low Risk to Low Risk of landslip affecting the property for
development approval. Based on the findings outlined previously, we assess that there is a Low
Risk of slope instability affecting the proposed residence provided that the geotechnical
recommendations included in this report are implemented.




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