Abstract The composite liner system consisting of geomembrane (GMB) and geosynthetic clay liner (GCL) has been widely used in landfills. Although there have been a lot of studies on the monotonic shear behavior of GMB/GCL composite liner, the dynamic test data are still very limited and consequently, the dynamic shear mechanism is not clear. A series of displacement-controlled cyclic shear tests were conducted to study the shear behavior of GMB/GCL composite liner, including the shear stress versus horizontal displacement relationships, backbone curves, and shear strengths. Hysteretic loops in the shape of parallelogram were obtained and equivalent linear analyses revealed that the secant shear stiffness decreased and the damping ratio increased with the rise in loading cycles. According to the test results, it is generally acceptable to predict the dynamic peak strength of a GMB/GCL composite liner with its static strength envelope. Furthermore, the dynamic softening mechanism and rate-dependent shear stiffnesses were well described by the proposed equations, which also facilitate the accurate modeling of the cyclic shear behavior.

中文翻译：

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GMB/GCL复合衬垫的循环剪切行为

摘要 由土工膜（GMB）和土工合成粘土衬垫（GCL）组成的复合衬垫系统已广泛应用于垃圾填埋场。尽管已经有大量关于GMB/GCL复合衬里单调剪切行为的研究，但动态试验数据仍然非常有限，因此动态剪切机制尚不清楚。进行了一系列位移控制循环剪切试验以研究 GMB/GCL 复合衬里的剪切行为，包括剪切应力与水平位移的关系、骨架曲线和剪切强度。得到平行四边形的滞回环，等效线性分析表明，随着加载周期的增加，割线剪切刚度降低，阻尼比增加。根据测试结果，用静态强度包络线预测 GMB/GCL 复合衬里的动态峰值强度通常是可以接受的。此外，所提出的方程很好地描述了动态软化机制和与速率相关的剪切刚度，这也有助于循环剪切行为的准确建模。