The Centrifuge Shaking Table And Large Shaking Table Experimental Study On Sand Liquefaction Of Free Field

Soil liquefaction during the earthquake is one of the main reasons of foundation failure and serious damage to construction and engineering.Now there are a wealth of research results for saturated sand liquefaction problem,which are mainly concentrated in two aspects: one is based on seismic damage data using statistical regression method to give a variety of empirical methods;the second is the study of liquefaction mechanism and anti-liquefaction strength of sand by using dynamic triaxial test.However the using of large-scale shaking table and centrifuge shaking table joint test research on liquefaction mechanism is still rare.In this paper,a comparative experiment of large-scale shaking table test and centrifuge shaking table test is carried out on the free sand.The test results are verified by the finite element software Open Sees.The purpose of this paper is to analyze the rationality of the two kinds of shaking table test,and to study the acceleration characteristics and the development law of pore water pressure of the saturated sand after liquefaction.The result can provide reference for the seismic design of geotechnical structure.The main work of this paper is as follows:1.Designed the centrifugal shaking table saturated sand liquefaction test and large-scale seismic simulation shaking table test program,and completed two kinds of shaking table test which simulating saturated sand seismic liquefaction.2.The results of the two shaking tables are analyzed and compared in detail.The results show that the stress and strain of the centrifuge shaking table test are consistent with the prototype.The centrifuge shaking table test can simulate the stress condition in the prototype stress field and can reproduce the dynamic response of prototype in the actual stress conditions.Large-scale shaking table test which gravity plays a major role in the study,can not meet the stress and strain of the similar relationship together,but it can still qualitative response to some of the law of liquefaction.3.The finite element software Open Sees were used to simulate the two shaking table tests.The results show that the centrifuge shaking table test and the numerical simulation are consistent with the seismic response in large earthquakes.And in the medium earthquake the upper soil layer consistent.This shows that the numerical simulation and centrifuge shaking table test coincide,you can use the finite element software Open Sees to study numerical simulation of saturated site seismic liquefaction problem.There are some differences between the numerical simulation and the large-scale shaking table test.The liquefaction degree of large-scale shaking table testis low.The large-scale shaking table test is not reasonable enough to simulate liquefaction of saturated sand.It can only do some qualitative research on liquefaction law.