填埋场复合衬垫系统直剪试验的数值模拟

 考虑填埋场衬垫系统材料间的接触特性,建立了复合衬垫系统直剪试验的有限元模型,采用ANSYS程序对填埋场复合衬垫系统的直剪试验过程进行了数值仿真分析。给出了不同法向力作用下不同加载时步衬垫系统中土工膜-黏土界面的剪应力云图,研究了界面内剪应力的分布情况,分析了接触面最大剪应力出现的位置及界面切应力变化特征;绘制了衬垫系统界面的应力-位移关系曲线,探讨不同法向力作用下不同位置点沿剪切位移方向的切应力τ_zy和垂直剪切位移方向的切应力τ_zx变化特点。结果表明,随法向力增加,界面切应力-位移曲线的硬化现象越明显;界面边缘位置处的切应力较大是界面破坏的源头;数值模拟可以再现试验发生的宏观现象,这是研究衬垫系统内部作用机理的一种有效途径。

Numerical Simulation of Landfill Liner System in Direct Shear Test

This paper investigates the shearing behavior of the liner system by using the ANSYS software. The numerical model of the direct shear test is built. The shear stress nephograms of the liner system between the geomembrane and the clay in different load steps under different normal pressures indicate the locations of the maximum shear stress, and the characteristics of the interface shear stress-displacement relations. It is shown that the stress-displacement curve does not display a hardening behavior under a low normal pressure, however, with the increase of the normal pressure the hardening behavior of the stress-displacement curve becomes more evident. The shear stress at the edge is larger than that in other places in the model. The macroscopic phenomena of the direct shear test are reproduced by the numerical simulations, and it is indicated that the numerical simulations is an effective way to study the mechanism of the internal liner system.