土工膜-土工布界面动力剪切特性试验研究

糙面土工膜（GMX）和无纺土工布（GT）是垃圾填埋场中周边衬垫系统的重要组成部分，其界面特性对于整体填埋场的稳定性尤为重要。但是，目前对GMX-GT界面的动力剪切特性研究较少。为此，利用大型直剪仪，开展了一系列全饱和条件及干燥条件下GMX-GT界面的循环剪切试验，主要研究了竖向应力、位移幅值和循环次数等对GMX-GT界面动力剪切特性的影响，并对比分析了全饱和及干燥两种条件下GMX-GT界面动力剪切特性的差异。研究结果表明，随着位移幅值的增加，GMX-GT界面呈现出由剪切硬化向剪切软化转变的特性。循环剪切作用使得界面的内摩擦角随着位移幅值的增加而增大。GMX-GT界面主要表现为剪缩特性，且总剪缩量随竖向应力、位移幅值和循环次数的增加而增加。剪切刚度随竖向应力和循环次数的增大而增大，随位移幅值的增大而减小。阻尼比随位移幅值的增大而增大，随循环次数的增加而减小，说明位移幅值会增加GMX-GT界面的能量的耗散。GMX-GT界面在干燥条件下的破坏模式与饱和条件下的存在明显差异，干燥条件下GT内部的破坏更加显著，全饱和条件下GMX表面的破坏更加明显。

Experimental study on dynamic shear characteristics of a geomembrane-geotextile interface

Textured geomembrane(GMX) and non-woven geotextile(GT) are important components of the liner system in MSW landfills. GMX-GT interface characteristics are sensitive to the stability of landfills. However, the dynamic behavior of the GMX-GT interface is not well understood. A series of cyclic direct shear tests was conducted on the GMX-GT interface under dry and fully saturated conditions. The effects of vertical stress, displacement amplitude, and cycle times on the dynamic behavior of the GMX-GT interface were studied. The dynamic behaviors of the GMX-GT interface under dry and fully saturated conditions were compared.The results demonstrated that the GMX-GT interface changed from shear hardening to shear softening with the increase of displacement amplitude. Meanwhile, the internal friction angle of the GMX-GT interface increased with the increase of displacement amplitude due to the cyclic shear. The GMX-GT interface was mainly characterized by shear shrinkage. The total shear shrinkage increased with the increase of vertical stress, displacement amplitude and cycle times. The shear stiffness increased with the increase of vertical stress and cycle times, while decreased with the increase of displacement amplitude. The damping ratio increased with the increase of displacement amplitude and decreased with the increase of cycle times, indicating that the displacement amplitude increased the energy dissipation of GMX-GT interface. The failure pattern was obvious different under the two conditions. The internal failure of GT was more significant under dry conditions, and the surface failure of GMX was more obvious under fully saturated conditions.