The Thredbo Landslide, although very small by most standards, was Australia’s most significant landslide in terms of societal impact with the highest death toll (18 people) and probably the highest indirect economic loss. The official report on the tragedy by the Coroner found: “The Alpine Way fill embankment which ran… above Thredbo Village was in a marginally stable state and extremely vulnerable to collapse if saturated by water.” “The propensity of the Alpine Way to landsliding which could lead to destruction of lodges and serious injury to persons within them was known.” But despite this, a water main was approved and placed in the Alpine Way embankment. The main was constructed of materials that could not withstand movements. This situation occurred above a site where: “The stability and geotechnical problems… were recognised and understood before any development of the Village in this area.” There are many lessons to be learned from the investigation and understanding of the landslide, both in technical terms and for the geotechnical profession as a whole. In particular, the Coroner also found that: “The geotechnical community needs to evaluate the way it conducts its investigations to ensure the investigations be undertaken having regard to the potential effect of instability on human life and the risk of loss of life or injury.” The presentation focussed on the landslide mechanism, the strength parameters, the method of analysis, causes and contributing factors, historical perspective, risk and lessons for the profession.
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