Importance of Advanced Analyses in Liquefaction Hazard Studies

This paper presents the results of liquefaction hazard analyses for four slopes along a deep-water canyon. The slopes are composed of mainly clay-like soil; however, the top 2–7 m of three of the slopes contains clayey-sand layers that were found to be susceptible to liquefaction. As a result, liquefaction triggering and consequences were evaluated by performing (1) three different CPT-based liquefaction triggering analyses; (2) 1D nonlinear effective stress analyses with three different pore pressure generation models; and (3) 2D nonlinear effective stress analyses using an advanced constitutive model. The results highlight the benefit of performing advanced analyses calibrated with site specific data. Simplified CPT triggering analyses were overly conservative, while 1D effective stress analyses calibrated with index parameters predicted no liquefaction compared to the 1D and 2D analyses that were calibrated with stress controlled cyclic DSS tests.