Site Factors Controlling Liquefaction

A finite element procedure for determining the dynamic response and liquefaction susceptibility of a deposit of saturated sand subjected to an arbitrary bedrock acceleration is developed. The method is structured in accordance with the generalized Biot constitutive equations for an inelastic two-phase medium, and it includes a law of the endochronic type to model the deviatoric constitutive behavior of the sand. The approach has the capability of accounting for: (1)Strain hardening and softening; (2)densification; (3)hysteretic and viscous damping; (4)the development of pore pressure due to volume change; and (5)consolidation due to internal pressure generation. The results reported in this investigation demonstrate that site factors, such as the shear resistance of the overburden, seepage conditions, nature of the loading history, layer thickness, bulk compressibility, and phase coupling, greatly affect the pore pressure increase in saturated sand layers subjected to a seismic excitation.