Variation of Permeability during Liquefaction and Its Effects on Seismic Response of Saturated Sand Deposits

Liquefaction phenomenon causes considerable increase in the soil permeability due to creation of easier paths for water flow. For an accurate modeling of seismic behavior of saturated sand deposits, in addition to properly modeling contraction behavior of liquefied sand, variation of ermeability coefficient during liquefaction should be taken into account. In this paper the effects of variation of permeability during liquefaction on soil seismic response is studied using a fully coupled dynamic analysis. A well calibrated critical state two-surface plasticity model has been mployed in the numerical analysis which is capable of accounting for the volumetric/shear response of soil skeleton in a wide range of densities (void ratios) and confining pressures. The OpenSees platform is used to conduct the numerical simulations. The simulation results indicate that incorporating the permeability variation in the numerical model is necessary for capturing both pore pressure and settlement responses of a liquefiable soil mass.