Reference Document - OPW25 0085 (AS Published)

    Analysis was undertaken for specified slip circle centroids (over a grid) and radii to assess global
     slope instability. The adopted ground surface profile was based on the steepest slope measured
     during the field investigation across the likely building areas, that being about 17°. The analysis
     returned an acceptable minimum FOS of at least 1.5 for both short-term and long-term conditions.
    This result indicates that the industry standard for short term conditions (FOS≥1.3, e.g. for shallow
     groundwater) and the minimum long term conditions FOS against slope instability for hillside
     development (≥1.5) would be achievable for the proposed development.




Text Figure 12: Slope/W analysis output for proposed residential construction – short term conditions

Our analysis indicates that an acceptable FOS against slope instability could be achieved for the new
residential development and that there would be a Low Risk of slope instability, subject to
implementation of the recommendations given in Section 6.




Geo-Environmental Investigation for Proposed Subdivision
7 February 2025 | 24386-001-Rev0                                                                             15