Assessment of post-liquefaction consolidation settlement

This paper presents a simplified procedure for the evaluation of the free-field consolida- tion settlement induced by liquefaction, using the results of 1D site response analysis in effective stress and a simplified approach based on empirical chart. The excess pore water pressures induced by the seismic action are generated by both a simple stress-based model implemented on a non-linear dynamic analysis and a simplified relationship between the safety factor against liquefaction and the excess pore pressure. The post-cyclic settlement is finally calculated on the obtained distribution of excess pore water pressure along the soil column. The proposed method has been used to estimate the consolidation settlements in a centrifuge test and in well-documented case histories of widespread liquefaction: Treasure Island and Marina District after the 1989 Loma Prieta earthquake. The results have been compared to the measured settlements and to the values obtained by previous studies. It is shown that the proposed approach leads to a much more accurate estimate of the post- liquefaction consolidation settlement, with just a little increase of the calculation effort.