Engineers Australia

Problems with liquefaction criteria and their application in Australia

R. Semple


In many parts of the world, including Australia, the state of practice in assessing if liquefaction will occur is based on the recommendations of Youd et al. (2001) which arose from workshops convened in the United States by NCEER (now MCEER). In some regards, the final publication did not so much represent a consensus view as a compromise between differing opinions within the expert group. Since then, disagreements over key aspects of liquefaction assessment in North America have increased to the point of chaos (Youd, 2011). There is little awareness in Australia of this situation nor appreciation of the NCEER limitations in applying these recommendations. Poorly informed decisions are increasing costs and causing project delays. This paper presents no original research but is an attempt by a practising geotechnical engineer to point out some problematic aspect of the NCEER liquefaction criteria, and of current recommendations in the literature and in so doing to encourage other practitioners and regulators to consider reasonable adjustments or alternatives.