循环加荷条件下饱和砂土液化细观数值模拟

利用离散单元法中的二维颗粒流方法(particle flow code in 2-dimension,PFC2D),通过对双轴数值试样施加循环等幅应变且控制加荷过程中试样体积(面积)不变的方法,模拟了循环加荷条件下饱和砂土的液化特性。在得到试样液化宏观力学响应的同时,分析了液化过程中内部平均接触数的变化规律。进一步研究了应变幅值、围压对数值试样液化特性的影响,并与室内试验规律进行了对比。结果表明,数值模拟能够定性地反映饱和砂土振动液化的一般规律,数值模拟得到的应变幅值、围压对试样抗液化强度的影响规律符合实际砂土室内试验规律。

Micro-mechanical simulation of liquefaction behavior of saturated sand under cyclic loading

The 2-D particle flow code(PFC~(2D)) approach of discrete element method is applied to simulate the liquefaction behavior of saturated sand under cyclic loading. In the numerical simulation the sample is exerted by the loading with cyclic uniform strain amplitude and keeping the volume unchanged.The macroscopic liquefaction response is obtained and the variation law of average internal co-ordination number in the process of liquefaction is analyzed.The effects of cyclic strain amplitude and confining pressure on liquefaction behavior obtained from numerical simulation are further analyzed by comparing the result with laboratory test data.It is found that the numerical simulation can quantitatively reflect the general characteristics of liquefaction behavior of saturated sand under cyclic loading,and the law of liquefaction resistance affected by cyclic strain amplitude and confining pressure is conform with the test result.