加肋土工膜与砂性土界面相互作用机制分析

Analysis of interaction mechanism of reinforced geomembrane and sandy soil interface

针对填埋场衬垫系统薄弱界面容易失稳,基于前期已完成的高密度聚乙烯(HDPE)加肋土工膜与砂性土界面直剪试验,以及结合试验结果对界面剪切特性及试样破坏形态分析的基础上,探讨了加肋土工膜与砂性土界面相互作用机制,给出了加肋土工膜与砂性土界面总阻力由面摩阻力、肋块所受端承阻力和侧摩阻力3部分组成的具体表达式,其中,肋块所受端承阻力是基于塑性滑移场理论建立起来的。同时,认为肋块端承阻力是提高加肋土工膜与砂性土界面剪切强度的主要原因,尤其在较高法向应力下,肋块端承阻力更能得到充分发挥。理论分析与试验结果较为吻合,该表达式能合理反映加肋土工膜与砂性土界面的总阻力。

Interface instability between high-density pdyethylene （HDPE） geomembrane and sand is a main reason for landfill structural failure on lining interface. A series of direct shear tests are carded out to investigate interfacial characteristics and specimen failure types of a novel geosynthetics-reinforced HDPE geomembrane and sandy soil interface. Based on the results of direct shear tests, the interaction mechanism of interface is analyzed. It is proposed that the total resistance of interface between reinforced geomembrane and sandy soil is made up of skin friction resistance, side frictional resistance and bearing resistance of reinforcement. Beating resistance of reinforcement is given by using the theory of slip line field. Results also show that the interface shear strength is significantly enhanced by the hearing resistance of reinforcement, especially in the higher normal stress. The results show that the theoretical value and experimental value varies in the same trend. The analytic solutions can reasonably indicate the interface total resistance.