Liquefaction assessment based on numerical simulations and simplified methods: A deep soil deposit case study in the Greater Lisbon

Abstract

The accurate estimation of earthquake-induced liquefaction damage requires detailed ground response analysis, which does not generally consider liquefaction. This paper presents a well-documented pilot site where different approaches to estimate surface ground motion were compared. A simplified stress-based method and non-linear dynamic effective stress numerical analyses were used to identify liquefaction. HVSR curves were used to validate the numerical analyses and laboratory test results were employed to calibrate an advanced constitutive model capable of reproducing liquefaction stress-strain behaviour and pore water pressure generation.1D non-linear elastic numerical analysis evidenced high shear strains in weak soil layers where liquefaction may occur. When PM4sand model was used to simulate liquefaction behaviour in sandy layers, 1D and 2D model responses were rather similar, since liquefaction occurs predominantly at a sandy layer that extends across the valley. Therefore, 1D horizontally infinite layers seems to be a good approximation of the 2D response of this valley.