A modified pressure dependent multi-yield surface model for simulation of LEAP-Asia-2019 centrifuge experiments

Abstract

A modified flow rule has been introduced into a pressure dependent multi-yield surface model for predicting the liquefaction of laboratory soil element tests and centrifuge experiments. The plastic potential function within the contractive phase in the flow rule of the constitutive model has been adjusted for better estimating the accumulation rate of plastic volumetric strain and the generation rate of excess pore water pressure. The modification of flow rule was mainly employed for achieving successful calibration of model parameters with the laboratory soil element tests and obtaining better predictions of the seismic response of LEAP-Asia-2019 centrifuge model tests. A calibration process of the constitutive model was firstly performed through numerical simulation of cyclic torsional shear tests of Ottawa F-65 sand samples with different relative densities under various cyclic stress ratios, and the estimation procedures of new parameters are provided. Then Type-B and Type-C numerical simulations were carried out for centrifuge experiments of a mildly sloping ground of Ottawa F-65 sand subjected to ramped sinusoidal input motions. The modified constitutive model could reasonably simulate the seismic response for almost all centrifuge model tests using the same set of model parameters.