210533 - 108 Black Mountain Range Road, BLACK MOUNTAIN - Slope Stability Report

Total Concept Homes                                                                                   20332-003-Rev0
                                                                                                         16 June 2022




             Text Figure 10: Footing depth required to minimise the risk of undermining and surcharge loading



Footing bases must be cleaned following mechanical excavation to expose undisturbed materials over the
full base area. Should bored piles be adopted, it is recommended that the piling contractor have a ‘mud
bucket’ or similar device to enable clean out of the pile bases. ‘Spinning’ of the augers is not acceptable
and will not sufficiently remove drill spoil from pile bases. A structural/geotechnical RPEQ should inspect
the footing excavations to confirm appropriate foundation materials and cleanliness prior to pouring
concrete.

If any soil conditions encountered during construction are found to differ from those noted above, Tectonic
and Ground Drill must be notified immediately and an inspection carried out to determine if changes to
footing design are required.

4.4       Retaining Structures
As a minimum any retaining walls must be founded as described in Section 4.3 above. Engineer design and
certification of retaining walls is required where such walls:

          Exceed 1 m height.
          Are subjected to surcharge loads (e.g. from backslope, adjacent structures, etc.).
          Are located within close proximity to existing structures.

Retaining structures should be engineer designed in accordance with AS4678-2002 Earth-retaining
structures. We suggest the parameters given in Table 3 overleaf may be adopted for retaining wall design.




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