加肋土工膜与砂土界面中附加应力计算

土工膜与砂土界面力学特性直接影响着填埋场衬垫系统的稳定性。依据弹性力学和土力学的基本理论，推导出加肋土工膜与砂土界面附近砂土中附加应力解析解，得到相应的应力分布。分析结果表明，加肋土工膜与砂土界面中附加应力等值线以双曲线型拱、扩肩型拱和圆弧型拱这3种分布形态存在的，砂土中任意点附加应力分布形态只与肋块长度、肋块表面距离远近有关，与肋块所受端承阻应力无关；在相同条件下，条形肋块比块状肋块对砂土附加应力的影响大，条状加肋土工膜能更有效地提高界面的剪切性能；离肋块表面距离越远，砂土中附加应力值越小，当与肋块表面距离达到12 mm时，这时砂土中附加应力几乎为0，也即肋块对其附近砂土的影响范围为12 mm左右。

A formula for calculating additional stresses in interface between geomembrane and sand

The mechanical property of interface between geomembrane and sand is a critical problem in stability analysis of landfill liner system. Based on basic theories of elastic mechanics and soil mechanics, the analytical solution of additional stress is given. The additional stress distribution of sandy soil near the interface is analyzed. The results show that there are three kinds of distribution form of additional stress isolines, which are hyperbolic type arch, enlarge shoulder arch type and circular arc arch. The additional stress distribution patterns are only related with the length of reinforcement and the distance from the reinforcement surface. There are no relation to the bearing stress of reinforcement. Under the same conditions, the effect of strip reinforced geomembrane is larger than that of lump reinforced geomembrane. So the strip reinforced geomembrane can improve the interface shear performance more effectively. The farther the sandy soil from the interface, the weaker the additional stress. When the distance from the reinforcement surface is up to 12 mm, the additional stress is close to zero. That is to say, the range of influence of reinforcement is about 12 mm.