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高密度聚乙烯(high-density polyethylene,简称HDPE)土工膜与土之间的抗剪强度较低是填埋场沿底部衬垫失稳的一个重要的原因。尽管糙面土工膜与黏土之间的摩擦系数较大,但随着应力积累,糙面土工膜很容易被拉裂,或者由于表面的颗粒被磨掉而使界面摩擦性能降低。在传统土工膜的基础上,提出了一种非满布单层加肋土工膜,并进行大量的界面直剪试验,研究在不同正应力和加肋间距下土工膜与砂土之间的界面特性、强度特性。试验结果表明,条状土工膜提高的是黏聚力,其内摩擦角有所下降,而块状土工膜黏聚力和内摩擦角都有很大程度的提高;随着加肋间距的减小,黏聚力逐渐的增大,而内摩擦角超过一定值后,又随着加肋间距的增加逐渐减小,这说明加肋间距存在一个最优值。加肋土工膜相比于光面土工膜、糙面土工膜,在提高界面抗剪强度的同时,依旧保持其较好抗拉裂性能,是一种较好的新型土工合成材料。
The low shear strength between high-density polyethylene (HDPE) geomembrane and soil is an important reason for the instability of the landfill along the bottom liner. Although the coefficient of friction between the rough geomembrane and the clay is large, as the stress accumulates, the rough geomembrane can be easily cracked, or the friction performance of the interface can be reduced because the surface particles are worn away. Based on the traditional geomembrane, a non-full-thickness single-layer ribbed geomembrane is proposed, and a large number of interface shear tests are carried out to study the interface between geomembrane and sand under different normal stresses and rib spacing Characteristics, strength characteristics. The test results show that the strip geomembrane is cohesive, its internal friction angle decreases, while the mass cohesion and internal friction angle of the block geomembrane have been greatly improved; with the increase of rib spacing Small, cohesion gradually increased, and the internal friction angle exceeds a certain value, but also with the increase of rib spacing increases, indicating that there is an optimal value of rib spacing. Compared with the smooth geomembrane and matte geomembrane, the latticed geomembrane is still a good new type of geosynthetics while improving the interface shear strength.