24-01-2020 - Appeal No. 245 of 2019 - Final Order of Judge Rackemann · 51987.2951.01

McInnes Wilson Lawyers

The vertical cut adopted in Case 1 assumes that erosion of the coffee rock will occur during the storm event.
This is a conservative approach as coffee rock is known to be resistant to erosion. The ‘conservative’
approach does, however, account for possible variation in coffee rock thickness/density at the toe of the
dune.
The modelling (refer Appendix B) indicates an acceptable FOS for the proposed pool supported on micro-
piles. The micro-piles will also improve the overall stability of the dune in this area, and will not impact
adjacent properties. The micro-piles must be founded into the underlying natural dense or very dense sand.
Micro-piles can be installed using equipment to suit the site’s access constraints. A conceptual micro-pile
design provided by PCA Ground Engineering is attached in Appendix C. Detailed design will be required by
the piling contractor.
The following additional recommendations are made for the proposed development:

▪       Disturbance to the surrounding slopes should be kept to a minimum (vegetation must be maintained
        below the proposed pool)
▪       Revegetation of any bare slopes around the development should be undertaken
▪       Additional fill must not be placed on the slope
▪       Excavations into the upper slope should be limited, with adequate
        temporary/permanent support provided. Excavations in the middle or lower
        portions of the slope must be avoided
▪       Concentrated stormwater flows down the slope must be prevented
▪       Ground vibrations from earthworks should be minimised and monitored. Dilapidation surveys of
        adjacent buildings/structures are recommended prior to construction works.




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