EFFECT OF SEISMIC LOAD TYPE AND RELATIVE DENSITY ON LIQUEFACTION DEFORMATION OF SATURATED SAND

This paper is based on the finite element platform Opensees. It established a one-dimensional shear beam soil column model with variable permeability coefficient and the accuracy of the model was verified by a centrifuge test results. The target is to explore the effect of seismic load type and relative density of sand on liquefaction deformation of saturated sand. Therefore, We selected the El-Centro seismic wave and Northridge seismic wave as inputting load. The simulated vertical displacement and excess pore pressure ratio of soil column under impact and vibration seismic wave were compared and analyzed when the relative density of sand was different. The results show that the vertical displacement under the vibration seismic wave is obviously larger than impact type; The increase of relative density can effectively reduce the vertical settlement of soil, and the effect is more obvious under the action of vibration seismic wave than that of impact seismic wave; The maximum pore pressure ratio of shock type seismic wave is larger than that of vibration type seismic wave, but the duration of high pore pressure is shorter and the dissipation process of pore pressure is faster; Loose sand is easier to achieve liquefaction conditions.