垃圾填埋场沿底部衬垫双层界面失稳破坏分析

摘要

The shear strength of geomembrane /clay interface and geomembrane /geotextile interface in the landfill liner systems are very low,which will result in the instability failure of the landfill.Three phases inter-face constitutive model is developed to describe the softening characteristic of these interfaces.Then,using the finite difference software,the effects of various parameters on the interface shear stress and displacement are analysed The results show that with the increase of elastic modulus,the interface displacement and shear stress increase at the base,while decreasing at the black slope.Landfill height and waste density have the same effects on the interface displacement and shear stress.And the back slope gradient has great effect on the in-terface displacement.The comparative analysis of GT/GMand GM/soil interfaces shows that the failure gener-ally occurs at the interface with smaller shear strength.%垃圾填埋场底部衬垫系统中黏土-土工膜（GM）界面和土工织物（GT）-土工膜界面的剪切强度较低，极易沿界面发生失稳破坏。提出三阶段界面本构模型描述界面的软化特性，采用有限差分程序建立计算模型，研究了垃圾体弹性模量、密度、高度和背坡坡度变化对界面剪应力和剪切位移的影响。分析结果表明：随着垃圾体弹性模量的增加，基地处界面剪切位移和剪应力均逐渐增大，而背坡处界面剪切位移和剪应力逐渐减小；随着垃圾体密度和填埋高度的增加，界面剪应力和剪切位移均逐渐增大，而背坡坡度对界面剪切位移影响较大；通过 GT/GM界面和 GM/地基土界面剪应力和剪切位移的对比分析可知，界面失稳破坏往往发生在抗剪强度较小的界面。