为了研究垃圾填埋场衬垫系统中加肋土工膜与砂土界面特性, 通过对比室内拉拔试验, 运用离散单元法的二维颗粒流程序(2D particle flow code, PFC$^{\rm 2D})$, 模拟了不同加肋高度和温度组合下的加肋土工膜与砂土界面拉拔试验, 得到了加肋土工膜与砂土界面的宏观应力-应变曲线、细观颗粒间位移场和应力场的变化规律. 研究结果表明: 加肋土工膜与砂土界面的拉拔应力明显优于光面土工膜($h=0$ mm)与砂土界面; 界面极限拉拔应力随着加肋高度的增加而增大, 随着温度的升高而减小; 界面摩擦系数随着温度的升高而减小. 还从细观角度(颗粒位移和内部接触力)模拟研究了加肋土工膜与砂土界面拉拔试验. 研究结果表明: 加肋土工膜与砂土界面附近砂土颗粒的位移较大, 颗粒整体向左上方移动, 而肋块后部上方的砂土由于法向应力作用向下运动; 随着温度的升高或者加肋高度的减小, 加肋土工膜与砂土界面附近的颗粒位移变大, 稳定性变差; 拉拔模型内部左侧的接触力较大, 加肋土工膜附近的接触力也较大, 并向上下两边逐渐减小; 随着加肋高度的增加或者温度的降低, 加肋土工膜与砂土界面附近土体内部的接触力明显增大. 研究结果从宏观到细观较全面地描述了加肋土工膜与砂土界面拉拔试验的全过程.

The features of a ribbed geomembrane and sandy soil interface in a landfill liner system were studied by comparing the results of an indoor experiment and a two-dimensional particle flow code (PFC$^{\rm 2D})$ simulation using the discrete element method. An interface drawing test of the ribbed geomembrane and sandy soil interface was conducted under different combinations of ribbed heights and temperatures. Then, the macroscopic stress-strain curves of the ribbed geomembrane and sandy soil interface, the changing rule of the displacement field of microscopic particles, and the stress field were investigated. The results showed that the tensile stress of the ribbed geomembrane and sandy soil interface was superior to that of the smooth geomembrane ($h =0$ mm) and sandy soil interface. The drawing stress limit of the interface increased with the increase in rib height, and decreased with the increase in temperature. In addition, the friction coefficient of the interface decreased with the increase in temperature. Simulation of the microscopic aspects (particle displacement and internal contact force) also corresponded with the results of the ribbed geomembrane and sandy soil interface drawing experiment. The soil particle displacement near the ribbed geomembrane and sandy soil interface was larger, and the overall particles moved to the top left. The sandy soil at the top after the rib had downward movement owing to the normal stress. With an increase in temperature or decrease in rib height, the displacement of sand particles near the ribbed geomembrane and sandy soil interface increased, and the interface stability between the ribbed geomembrane and sandy soil became negligible. The contact forces on the left side of the drawing model and near the ribbed geomembrane were larger, and gradually decreased to the upper and lower sides. With an increase in rib height or a decrease in temperature, the contact force around the interface between the ribbed geomembrane and sandy soil increased. The entire process of drawing the ribbed geomembrane and sandy soil interface from macroscopic to microscopic was described.