Abstract: Interface instability between HDPE geomembrane and sand is a main reason for landfill structural failure on lining interface. Though frictional coefficient of textured geomembrane is large, it is easy to be splited by the huge tension force accumulated on the landfill lined slope, or to be weared and teared. A novel concept of reinforced HDPE geomembrane is proposed. A series of direct shear tests were carried out to investigate interfacial characteristics and stress mechanism under different normal stresses and spaces of reinforcement. Comparison was made between stress-strain relationship and strength property of reinforced geomembrane, smooth geomembrane and textured geomembrane. It was shown that cohesion of strip geomembrane was increased, internal frictional angle was reduced, while both of lump geomembrane were increased considerately. Along with decreasement of space, cohesion of reinforced geomembrane added. However there is a gradual reduction of internal frictional angle when it exceeds a specific value. Compared with smooth geomembrane and textured geomembrane, reinforced geomembrane, as is a new kind of geosynthetics, not only has a higher interface shear strength with sand, but also has a better rupture strength.

Key words: reinforced, geomembrane, shear stress, direct shear test