1.Shanghai University;2.Institute of Rock and Soil Mechanics, Chinese Academy of Sciences
National Natural Science Foundation of China(51778353; 51978390)；Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences (No.Z018007)；The Youth Innovation Promotion Association CAS (2017376)
结合H-V（Horizontal-Vertical）立体土工膜及传统水平土工膜衬垫与土相互作用的力学模型试验，利用基于离散元理论的颗粒流软件（particle flow code，PFC），对具有不同几何特征的土工膜与土之间的细观作用机理进行了系统地研究，探明了H-V立体土工膜衬垫宏观力学效应得以改善的微观机理。文章通过对比已完成土工膜复合衬垫模型试验所得的宏观力学特征，主要从细观角度，就不同几何特征土工膜衬垫与土颗粒相互之间的位移变化规律、土颗粒与膜之间的接触力分布、膜上的应力分布以及整体衬垫系统中竖向应力的分布等进行了研究。发现与传统水平土工膜相比，H-V立体土工膜除了具有传统水平土工膜与土之间的摩擦作用外，还有竖向膜部分对土颗粒附加作用的侧摩阻力和咬合力。竖向膜可以约束土颗粒的位移及力链从受荷中心向两侧方向的传递，并使得H-V立体土工膜与土形成良好的约束挤密区。这不仅可以延缓H-V立体土工膜衬垫内部形成连续滑移面，同时可以更有效地均化整体衬垫中的应力分布，使得相同上覆荷载下，H-V立体土工膜衬垫具有更小的整体沉降量和不均匀沉降。
Combined with the mechanical model test of interaction between soil and liner of H-V （Horizontal-Vertical）three-dimensional geomembrane and traditional horizontal geomembrane, particle flow code based on discrete element theory was used to analyze the micromechanism between the soil and the geomembrane with different geometric characteristics. Thus, the micromechanism of improving the macro mechanical effect of H-V three-dimensional geomembrane liner is proved. By comparing the macroscopic mechanical characteristics obtained from the model test of geomembrane composite liner, the article mainly studies the displacement change law between soil particles and geomembrane liner with different geometric characteristics, the contact force distribution between soil particles and geomembrane, the stress distribution on the geomembrane, and the vertical stress distribution in the integral liner system from the micro perspective. It is found that, compared with the traditional horizontal geomembrane, the H-V three-dimensional geomembrane has not only the friction between the traditional horizontal geomembrane and the soil but also the side friction and bite force of the vertical membrane on the soil particles. The vertical membrane can restrain the displacement of soil particles and the transmission of force chain from the load center to both sides, and make the H-V three-dimensional geomembrane and soil form a good constrained compaction area. This can not only delay the formation of continuous slip surface in the H-V three-dimensional geomembrane liner, but also more effectively homogenize the stress distribution in the integral liner, so that the H-V three-dimensional geomembrane liner has smaller overall settlement and uneven settlement under the same overlying load.