NUMERICAL SIMULATION OF SATURATED SAND LIQUEFACTION DISCRIMINATION AND AMPLIFICATION EFFECT

This paper aims to study the influencing factors of sand liquefaction identification and amplification effect under earthquake action. It established a one-dimensional shear beam soil column model based on the open source finite element platform OpenSees. The model used the sand constitutive developed in the boundary surface plastic model. Taking the cyclic stress ratio(CSR) and the cyclic resistance ratio(CRR)as the control indicators,the differences between two liquefaction identification methods were compared. We analyzed the influence of the seismic load type and the relative density of sand on the liquefaction identification and amplification effect. The research shows that compared with the numerical simulation results,the CSR calculated by the Seed simplified method is larger,and the possibility of judging the liquefaction of saturated sandy soil is higher. The shock-type seismic waves are more likely to cause liquefaction of saturated sandy soils than vibration-type seismic waves. The smaller the relative density of sand,the easier it is for the site to liquefy. The amplification factor increases with the decrease of the buried depth. The amplification effect caused by vibration-type seismic waves is generally greater than that of impact-type seismic waves. When the buried depth is large,the magnification factor decreases with the increase of the relative density.