Abstract Textured geomembrane (GMB) and nonwoven geotextile (GTX) are usually used together in liner systems of MSW landfills, but the low shear strength of GMB/GTX interface is extremely detrimental to the stability of landfills, especially under earthquake loading. To study the dynamic shear strength of the GMB/GTX interface, a series of displacement-controlled cyclic direct shear tests are conducted with a large-scale direct shear machine. Normal stress levels ranging from 100 to 1000 kPa and displacement amplitudes ranging from 5 to 25 mm are considered. To compare the failure mechanism, GMB and GTX specimens are tested in not only hydrated but also dry conditions. Different waveforms and excitation frequencies are also applied to analyze the effects of test conditions. It can be seen that the shear deformation develops totally along the GMB/GTX interface when specimens are fully hydrated, while the internal failure of GTX is induced in dry condition. Equivalent linear analyses reveal that the shear stiffness depends on normal stress and displacement amplitude, while the damping ratio is only affected by displacement amplitude. Variations of shear strength during the shear process indicate that the softening behavior of the GMB/GTX interface is closely related to cumulative displacement and normal stress level. Furthermore, based on test results, a positive correlation is summarized between the shear strength and displacement rate of the interface.

中文翻译：

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循环荷载作用下织构土工膜/非织造土工布界面的动态剪切行为

摘要 纹理土工膜（GMB）和非织造土工布（GTX）通常一起用于垃圾填埋场的衬垫系统，但GMB/GTX界面的低剪切强度对垃圾填埋场的稳定性极为不利，尤其是在地震荷载作用下。为了研究 GMB/GTX 界面的动态剪切强度，使用大型直剪机进行了一系列位移控制循环直剪试验。考虑了 100 到 1000 kPa 范围内的法向应力水平和 5 到 25 mm 范围内的位移幅度。为了比较失效机制，GMB 和 GTX 试样不仅在水合条件下而且在干燥条件下进行测试。还应用了不同的波形和激励频率来分析测试条件的影响。可以看出，当试样完全水化时，剪切变形完全沿 GMB/GTX 界面发展，而在干燥条件下会引起 GTX 的内部破坏。等效线性分析表明剪切刚度取决于法向应力和位移幅值，而阻尼比仅受位移幅值影响。剪切过程中剪切强度的变化表明 GMB/GTX 界面的软化行为与累积位移和法向应力水平密切相关。此外，基于测试结果，总结了界面的剪切强度和位移速率之间的正相关。等效线性分析表明剪切刚度取决于法向应力和位移幅值，而阻尼比仅受位移幅值影响。剪切过程中剪切强度的变化表明 GMB/GTX 界面的软化行为与累积位移和法向应力水平密切相关。此外，基于测试结果，总结了界面的剪切强度和位移速率之间的正相关。等效线性分析表明剪切刚度取决于法向应力和位移幅值，而阻尼比仅受位移幅值影响。剪切过程中剪切强度的变化表明 GMB/GTX 界面的软化行为与累积位移和法向应力水平密切相关。此外，基于测试结果，总结了界面的剪切强度和位移速率之间的正相关。