Settlement of liquefied sand after a strong earthquake

The paper presents the results of the numerical modelling of the liquefaction and subsequent settlement of a saturated sand layer induced by a large-amplitude shear wave coming from below. The repeated shear deformation caused by the dynamic disturbance results in the reduction of the effective pressure and liquefaction of the soil. The permanent changes in the effective stress are inhomogeneous. The liquefaction is localized in thin zones which emerge successively from the top to the bottom and divide the layer into several parts. Each zone of liquefaction isolates the above situated soil from the incoming wave. The settlement of the sand is found from the solution of the quasi-static problem of uniaxial compression. The settlement is presented as a function of the amplitude of the dynamic disturbance. Both the dynamic and the quasi-static problems are solved with a constitutive equation of hypoplasticity.