Triaxial Test And Analysis Of Seismic Liquefaction Of Saturated Sand

Destruction and collapse of breakwater and other geotechnical structures in earthquake often cause catastrophic loss of human life and property. Soil liquefaction is one of major reason for foundation failure, and there are many factors can affect the sand liquefaction.The theory of seismic sand liquefaction is far from adequate. The Analysis of Seismic Liquefaction on Saturated Sand is still an important and difficult research.Formerly, total stress method was the major method for analysis of breakwater and other embankment structures based on saturated sand foundation. Static analysis was mainly based on the Duncan-Chang model, dynamic analysis was mainly based on the equivalent linear model and the liquefaction’s discretion was mainly based on its safety factor. Although has made a great deal of research results, the method requires several models and parameters in the calculation process and the calculation process is complicated and is not entirely reasonable. The method also doesn’t take the impact of the vibration pore water pressure changes on the dynamic property of soil into account, so it cannot accurately analyze liquefaction under dynamic loading.The constitutive model of this paper is the generalized plasticity model. Based on generalized plasticity theory framework and successfully applied to many practical engineering, the generalized plasticity model can complete all the static and dynamic analysis of geotechnical structures with one set of parameter. As analysis method of this paper, effective stress method not only improves the calculation accuracy, but also calculates the changing process of pore water pressure and the possibility of liquefaction under dynamic loading.The present research is supported by the National Mege-project of Natural Science Foundation of China Function"Tailure mechanism and seismic safety evaluation of the nuclear power plant engineering struction under seism action"(No.51138001),the Natural Science Funds of Liaoning Province"Study on earthquake response of nuclear power plant’s draining shiele tunnel under complex ocean foundation conditions "(No.201102026) and the earthquake industry special funds for scientific research projects"Study on the earthquke response of the structures features and failure mechanism of nuclear powe plant’s draining structures(No.201208013)". The specific work is as follows.1. Conduct static and dynamic triaxial test on saturated sand under two densities with Tsz-6A strain triaxial apparatus and DS-2T cyclic triaxial apparatus. Test results are analyzed. 2. Simulate the generalized plasticity model parameter according to the test results, compare the difference between the test results and the model parameter to verify the reliability of the model parameter.3. Conduct elastoplastic analysis of the replacement-type, counter-pressure-type and regular breakwater, respectively, with effective stress method based on saturated soil dynamic consolidation theory and compare the effects of different liquefaction resistance measures on breakwater liquefaction according to pore water pressure and its ratio distribution.