粘性土的动力特性实验及数值模拟

使用产自日本的DTC-306型多功能电液伺服动态三轴仪,对粉质粘土进行动三轴试验。在试验提供的各种参数和数据的基础上,利用有限元程序ABAQUS建立动三轴试件的三维有限元模型,模拟在循环荷载作用下粉质粘土的动力变形特性;并通过与动三轴试验相关数据的大量对比分析,验证了模型的可靠性。然后在建立的三维有限元模型的基础上,进一步用数值模拟的方法研究了土体动力变形与各影响因素间的关系,得出如下结论:初始弹性模量、阻尼系数、受荷形式对土的塑性变形影响最大,应力幅值、围压、频率、加荷周数次之,加载波形的影响最小,不同波形对塑性变形的影响取决于荷载最大值时历时的长短。有限元数值模拟方法在一定程度上可以替代动三轴实验。

Experiment and Numerical Simulation of Dynamic Behavior for Cohesive Soils

The dynamic tri-axial instrument of DTC-306 made in Japan is used to make cyclic tri-axial test of silty clay under dynamical loading by load control.On the basis of various parameters and data offered from the test,utilizing common finite element procedure ABAQUS to set up the three-dimensional finite element model of the dynamic tri-axial sample,the dynamical deformation behavior of silty clay under cyclic load is simulated.Through a lot of contrast analysis to the dynamic tri-axial test relation data,the reliability of the model is validated.Then based on the finished three-dimensional finite element model,the relationship between dynamic deformation and the influence factors is researched,and the results are as follows: the first important influential factors of soil plastic deformation are initial elastic modulus,damping factor and type of cyclic load,then the magnitude of cyclic load,surrounding stress,frequency and the number of cyclic times,and the minimum influential factor is type of load wave.The numerical simulation method of finite element can substitute the dynamic tri-axial test to a certain extent.