Effect of different category of geogrid and sand layer on pull-out behaviour

Abstract

Geosynthetics are used as reinforcing elements in different soil structure: reinforced slops and walls; embankments on soft soils; reinforcement in the base layers of road construction; bridging of sinkholes or reinforced abutments. The pull-out test is one of the methods that used to study pull-out behaviour and soil-reinforcement interaction .In current study, the pull-out test has been modelled by finite element to investigate possibility of pull-out resistance enhancement of clay reinforced with three categories of geogrid (homogenous, coated woven, welded straps) embedded in thin layers of sand. Pull-out test on sand-geogrid, clay-sand-geogrid samples have been simulated at normal pressure of 50 kPa. Numerical results show the provision of thin layers around the geogrid. Significantly increase pull-out resistance of clay soil under monition loading conditions and optimum ratio sand layer thickness to box test height of 0.15 has been determined for maximum enhancement. The pull-out force increase with increasing the axial stiffness (EA) in Welded straps geogrid.