Liquefaction analysis of saturated soils taking into account variation in porosity and permeability with large deformation
A numerical method for liquefaction analysis of saturated soils with large deformation is presented. Formulations are based on Biot's two-phase mixture theory and the updated Lagrangian method. Governing equations consist of an equilibrium equation and one for mass conservation. Based on the u-p formulation, displacement of the soil skeleton and pore pressure are the two basic unknown variables. Governing equations are discretized by the FE-FD coupled method. A cyclic elasto-plastic constitutive model is used to describe the liquefaction behavior of saturated soils under dynamic loading. The coefficient of porosity is considered to vary with large deformation. The coefficient of permeability is assumed to be a function of the void ratio. The examples show the flexibility and applicability of the proposed method. Comparison is made between large and small strain solutions. The large deformation analysis shows that liquefaction occurs earlier in seabed deposits under wave action and deeper in the soil surrounding an embankment subjected to strong earthquake motion than it does in small strain analysis.
liquefaction saturated soils large deformation