ECM_22343520_v1_Geotechnical Investigation · 132000.200173.1

                                          PROPOSED RENOVATIONS
                                          2 ARAKOON CRESCENT, SUNSHINE BEACH




            Text Figure 12: Slope/W output for the proposed development

            Our analysis indicates that stability of the site hinges on the temporary and permanent retention systems.
            Provided that footings for the residence and structural walls are founded at least 1 m into medium dense (or
            denser) sands, and the existing timber sleeper wall to the east of the residence is replaced with a new
            engineer designed and certified structure founded on shear piles, the required minimum FOS for long-term
            stability (i.e. 1.5) could be achieved.

            Our limit equilibrium modelling indicates that relatively conventional building piles could be adopted for the
            proposed development generally; however, piles socketed at least 1 m into medium dense (or denser) sand
            designed with an unfactored shear force resistance of 100 kN/m (or equivalent) will be required beneath the
            new retaining wall to the east of the residence. It should be noted that required shear and bending
            resistance of the piles and their depth should be determined by inite element analyses based on all relevant
            loads including from structures (not included in our Slope/W modelling) and all soil, fill and landscaping
            loads. To facilitate a larger level garden/grassed area to the east of the residence, the new retaining wall
            could be located eastwards, however not beyond the current dune crest.

            Subject to implementation of the recommendations made in Section 6 during building works, there would be
            a Low Risk of slope instability affecting the proposed development.
            It should be noted that this modelling addresses the global stability of the proposed works; however, the
            stability of the retaining walls must be addressed by others as part of detailed design.




             24 February 2023
             Report No. 22484-001-Rev0                              13
Document Set ID: 22343520
Version: 1, Version Date: 16/03/2023