Abstract: The geosynthetic-soil interaction improved by adding sand layer between geosynthetics and clay was explored by using interface shear tests. By changing the grain size composition (coarse sand or fine sand) and the thickness of sand layer (1-3cm) in direct shear test and pull-out test, the specific influence of sand layer was analyzed. Results revealed that sand layer between geosynthetic reinforcement and clay could effectively enhance the strength of the interface, but the grain size composition and the thickness of sand layer had little influence on the shear strength of geosynthetic-sand interface under 25-75kPa normal stress.

Key words: reinforcement-sand-clay layer system, interface shear test, thickness of sand layer, grain size composition