Deng, W, O’Neill, K, Luu, K & Little, K 2013, 'Geotechnical reliability assessment of a large counterfort retaining wall', in PM Dight (ed.), Proceedings of the 2013 International Symposium on Slope Stability in Open Pit Mining and Civil Engineering
, Australian Centre for Geomechanics, Perth, pp. 569-582.
In the development of Barangaroo Headland Park in Sydney, a retaining wall was required to retain up to 18.5 m of fill and to form a physical barrier between the Headland Park fill and the Future Cultural Space. To minimise the quantity of imported select fill to the site and to provide a more impenetrable barrier to water and odours, a reinforced concrete counterfort wall solution was derived in conjunction with an anchoring system to reduce the base width. The counterfort wall is constrained by the adjacent excavation for the Future Cultural Space which is approximately 7 m deep and up to 7 m away from the proposed counterfort wall face.
Due to the significance of the structure, a supplementary geotechnical reliability assessment of the counterfort wall failure was undertaken in addition to the deterministic geotechnical design and assessments based on AS5100.3 in the detailed design stage. This paper presents the geotechnical reliability assessment carried out. The project background, and the elements of works which are relevant to the counterfort retaining wall, are introduced. The underlying ground conditions and geotechnical uncertainties are then described, with the assessment of the most likely values of the geotechnical parameters involved in computing the Factor of Safety by the deterministic method, and the standard deviations of the parameters that involve uncertainty and risk. The probabilities of failure for various geotechnical failure modes are then assessed. The major contributors to the standard deviation of the Factor of Safety are identified and measures to reduce these uncertainties that informed to the design are discussed. Finally, the significant contribution of the geotechnical reliability analysis to the detailed design of the counterfort wall is summarised, and remarks on the application of a reliability assessment in geotechnical design are made.
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