Attachment 3 - Revised Slope Stability Assessment

Brett Hage                                                                                          22328-001-Rev1
                                                                                                  17 November 2022




Text Figure 9: Slope/W Model output, groundwater at 1 m BGL (Ref. Figure 1 for approx. section line)


The key points from our analysis are summarised as follows:
       Unit weight and shear strength parameters adopted for the soil strata were taken from the mid to
        lower range of values recommended for similar materials in Appendix D of Australian Standard
        AS4678-2002 ‘Earth Retaining Structures’.
       Analyses were undertaken for a specified range of slip circle centroids and radii, with a minimum
        FOS value of 1.5 recorded for the longer term case, even where groundwater is assumed to
        proliferate at shallow depth (1 m BGL).
       This result meets the industry standard minimum FOS (i.e. ≥1.5) for long term conditions.

Our analysis indicates that the proposed development will achieve at least the required minimum FOS.
Subject to implementation of the recommendations made in Section 4 during building works, there would be
a Low Risk of slope instability affecting the proposed development.




                                                         10/19