堆石坝的土工膜与面板联合防渗结构中,土工膜与相接触的垫层材料之间的界面力学特性是关系坝体稳定性的关键因素。首先介绍了传统的土工膜界面力学特性直剪试验设备、试验原理及方法,并指出其在界面接触摩擦真实应力计算过程中的不足之处;然后,对传统的试验设备进行了改进,并对比分析了多种不同工况条件下2种试验设备的测试结果;最后,通过理论推导给出了传统试验测试方法中土工膜与界面之间真实剪切应力的修正计算公式,并进行了试验验证。结果表明新的土工膜接触剪切应力计算公式,能够在不改变传统试验测试方法的基础上,给出土工膜界面剪切作用下的真实应力结果。

In the rockfill dam’s united anti-seepage system, the mechanical properties of the interface between geomembrane and cushion material have important influence on the stability of the dam. Firstly,we introduce the test equipment, test principle and method of geomembrane’s interface mechanical properties, and point out the deficiency in the process of calculating the real stress of its contact friction at the interface. Then, the traditional test equipment is modified, and a comparative analysis of results by the two test equipments was conducted under different working conditions. Finally, the real shear stress of geomembrane in the traditional test method is modified through the theoretical derivation, which has been verified by the test experiment. The verification result shows that the shear stress formula can really describe the mechanical properties of the interface between geomembrane and cushion material under shear force.