Residual interface strength is mobilized along sideslopes of geosynthetic lined areas, such as landfill sideslope. Unfortunately, only the large displacement (LD) interface strength is measured in frequently used direct shear tests, which overpredicts the residual interface strength by about 40% because of limited continuous shear displacement and new geomembrane being introduced during the test. Commercial laboratories usually conduct direct shear tests in accordance with ASTM D5321-02 or ASTM D6243-13, which can only measure the LD interface strength. This paper suggests a method to estimate the residual interface strength from direct shear test results, which provides a better estimate of field interface strengths. The shear stres–displacement relationship from ring shear tests fits a power function, which can be used to extrapolate direct shear test results to the residual strength. This paper shows the power function can predict reasonable residual interface strengths from the shear stress–displacement relationship measured in direct shear tests. This method allows estimation of the residual strength data when only direct shear test results are available and prevents overprediction of the factor of safety (FoS) during slope stability evaluations.

中文翻译：

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从直接剪切测试推断残余 GMX/GDC 界面强度

剩余界面强度沿着土工合成材料衬里区域的边坡（例如垃圾填埋场边坡）进行调动。不幸的是，在常用的直接剪切试验中仅测量大位移（LD）界面强度，由于有限的连续剪切位移和试验过程中引入了新的土工膜，这将剩余界面强度高估了约40%。商业实验室通常按照ASTM D5321-02或ASTM D6243-13进行直接剪切测试，只能测量LD界面强度。本文提出了一种根据直剪试验结果估计残余界面强度的方法，该方法可以更好地估计现场界面强度。环剪试验的剪切应力-位移关系符合幂函数，可用于将直接剪切试验结果外推至残余强度。本文表明，幂函数可以根据直接剪切试验中测量的剪切应力-位移关系来预测合理的残余界面强度。该方法允许在只有直剪试验结果可用时估计剩余强度数据，并防止在边坡稳定性评估期间过度预测安全系数 (FoS)。