填埋场衬垫系统界面本构模型研究

典型垃圾填埋场衬垫系统由土/土工膜、土工膜/土工织物等多个界面组成，这些界面抗剪强度低，成为潜在的滑裂面，容易使填埋场发生沿界面的失稳破坏。本文根据大量土/土工膜界面直剪试验的研究，针对该界面的变形机理和应变软化特性，在前人研究的基础上确定了接触面的厚度，定义了接触面的切向应变和法向应变，将界面的变形分为3个阶段：弹性阶段，塑性阶段和残余阶段。同时提出了适合于土与土工膜界面的弹塑性本构模型。该本构模型参数较少，物理意义明确，运用简单方便。最后，结合Filz接触面直剪试验和钱学德单剪试验的结果，将通过该模型得到的拟合结果与之进行了对比验证分析。研究结果表明：本文提出的土与土工膜界面弹塑性本构模型是合理可行的，且建模方便，适用于工程实践。

STUDY ON INTERFACE CONSTITUTIVE MODEL IN LANDFILL LINER SYSTEM

In the landfill, liner systems typically contain a large number of material interfaces(soil/geomembrane or geomembrane/geosynthetics). These interfaces become potential slip surfaces because of the low shear strength, which results in the instability of landfill. Based on many direct shear tests, the deformation mechanism and strain softening property of soil/geomembrane interface, the interface thickness, tangential strain and normal strain are determined. The deformation of the interface is divided into three stages: elastic stage, plastic stage and residual stage. Above all, the elastic-plastic interface constitutive model is put forward. There are only a few parameters with clear physical meanings in the model. At last, the results using this model are compared with those of the interface direct shear tests and ring simple shear tests. The comparison results show that this model is reasonable and feasible, and can be used for practical engineering.