土工膜与土界面剪切特性细观研究

发布时间：2018-12-31 12:55

【摘要】：填埋场衬垫系统中,土与土工膜界面剪切强度较低,易造成失稳破坏。目前国内外学者主要采用室内试验对土与土工膜界面的宏观剪切特性进行研究,而对界面剪切特性的细观研究较少。为了从细观角度研究土与土工膜界面的剪切特性,本文采用Esy S-particle程序对土工膜与土界面直剪试验进行了离散元数值模拟分析。采用摩擦接触模型模拟砂土;采用黏结模型颗粒模拟土工膜,通过紧密排列土工膜颗粒以模拟土工膜的光滑表面。通过室内拟合试验,选取和校准材料的细观参数。分析结果表明,离散元模型能较好的模拟界面应力-应变关系;剪切带的厚度约为两倍平均土颗粒直径;剪切带中的土颗粒发生较大位移,孔隙比增大,而剪切带之外的土颗粒位移和孔隙比变化较小;随着剪切位移的增加,颗粒间接触力逐渐向左端集中,力链方向由垂直逐渐倾斜。
[Abstract]:In the landfill liner system, the interface shear strength of soil and geomembrane is low, which can easily lead to instability and failure. At present, domestic and foreign scholars mainly use laboratory tests to study the macroscopic shear characteristics of the interface between soil and geomembrane, but the mesoscopic research on the interface shear characteristics is less. In order to study the shear characteristics of the interface between soil and geomembrane from a mesoscopic point of view, a discrete element numerical simulation analysis of the direct shear test of the interface between geomembrane and soil was carried out by using Esy S-particle program. The sand is simulated by friction contact model and the geomembrane is simulated by bonding model particles, and the smooth surface of the geomembrane is simulated by tightly arranging the geomembrane particles. The mesoscopic parameters of materials were selected and calibrated by indoor fitting test. The results show that the discrete element model can simulate the stress-strain relationship of the interface and the thickness of the shear zone is about twice the average soil particle diameter. The larger displacement of soil particles and the increase of void ratio occur in the shear zone, but the change of soil particle displacement and porosity ratio outside the shear zone is relatively small. With the increase of shear displacement, the contact force between particles is gradually concentrated to the left end, and the direction of the force chain is inclined gradually from the vertical direction.
【作者单位】：同济大学地下建筑与工程系;
【基金】：国家重点基础研究发展计划“973计划”项目(2012CB719803)资助
【分类号】：TU43

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