Abstract：Composite liner systems are widely used in waste disposal landfills to minimize the potential contamination of the geo-environment. The shear stresses exerted by the gravity and settlement of waste may lead to tensile failure or sliding instability along the interfaces. Due to lack of understanding of shear stress transfer mechanism, the above engineering problems are still often occurring. A large-scale ramp model test apparatus is designed to study the shear stress transfer mechanism. Landfill process is successfully simulated by stacking sand bags, and progressive slope failure along the geomembrane/geotextile interface is revealed by the sliding control system. The test results show that when the shear stress induced by the vertical loading is less than the peak interface shear strength, the interface strength will not fall into a residual strength. However, when the shear stress exceeds the peak interface shear strength, the interface strength will quickly fall into a residual strength, which will result in sharp increase of the tension in the geotextile, and if it is serious, the geotextile will be completely broken.
 KOERNER R M, SOONG T Y. Stability assessment of ten large landfill failures[C]// Advances in Transportation and Geoenvironmental Systems Using Geosynthetics, 2000: 1–38.  QIAN Xue-de, KOERNER R M. Translational failure analysis of solid waste landfills including seismicity and leachate head calculations[R]. Philadelphia: Geosynthetic Research Institute, Drexel University, 2007.  QIAN Xue-de, KOERNER R M. Stability analysis for using engineered berm to increase landfill space[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2009, 135(8): 1082–1091.  詹良通, 管仁秋, 陈云敏, 等. 某填埋场垃圾堆体边坡失稳过程监测与反分析[J]. 岩石力学与工程学报, 2010, 29(8): 1697–1705. (ZHAN Liang-tong, GUAN Ren-qiu, CHEN Yun-min. Monitoring and back analyses of slope failure process at a landfill[J]. Chinese Journal of Rock Mechanics and Engineering, 2010, 29(8): 1697–1705. (in Chinese))  KOERNER R M. Designing with geosynthetics[M]. 4th ed. NJ, Prentice-Hall Inc, Englewood Cliffs, 1998.  VILLARD E, GOURC J P, FEKI N. Analysis of geosynthetics lining systems (GLS) undergoing large deformations[J]. Geotextiles and Geomembranes, 1999, 17: 17–32.  PALMEIRA E M, LIMA N R, et al. Interaction between soils and geosynthetic layers in large scale ramp tests[J]. Geosynthetics International, 2002, 9(2): 149–187.  PALMEIRA E M, VIANA N L. Effectiveness of geogrids as inclusions in cover soils of slopes of waste disposal areas[J]. Geotextile and Geomembrane, 2003, 21: 317–337.  FOWMES G J, DIXON N, JONES D R V. Validation of a numerical modelling technique for multilayered geosynthetic landfill lining systems[J]. Geotextiles and Geomembranes, 2008, 26(2): 109–121.  BRIAN L, GIRAND H, POULAIN D. Slope stability of lining systems-experimental modeling of friction at geosynthetic interfaces[J]. Geotextiles and Geomembranes, 2002, 20: 147–172.  JONES DRV, DIXON N. Landfill lining stability and integrity: the role of waste settlement[J]. Geotextiles and Geomembranes, 2005, 23(1): 27–53.  KOERNER R M, SOONG T Y, GONTAR A. Selected aspects of GCL shear strength testing[C]// Proceedings of Geo-Bento, Insatec Publications, France, 1998: 97–110.  THUSYANTHANA I, MADABHUSHIA S P G, SINGH S. Tension in geomembranes on landfill slopes under static and earthquake loading-centrifuge study[J]. Geotextiles and Geomembranes, 2007, 25: 78–95.  林伟岸, 詹良通, 陈云敏, 等. 含土工复合排水网衬里的界面剪切特性研究[J]. 岩土工程学报, 2010, 32(5): 693–697. (LIN Wei-an, ZHAN Liang-tong, CHEN Yun-min. Interface shear strength of the liners with geocomposite[J]. Chinese Journal of Geotechnical Engineering, 2010, 32(5): 693–697. (in Chinese))