Experimental research on shearing resistance property of geogrid-sand interface under normal cyclic load

A series of direct shear tests were performed by using self-developed large-scale interface shear apparatus to investigate the shearing resistance properties of sand-geogrid interface and compare the experimental results under normal cyclic load with those under static load. The test results demonstrate that the development trend of shear stress-displacement curves under cyclic load are similar to those under static load, but the shear curves under cyclic load show cyclic development characteristics; the relationships between the maximal shear stress of peak value and normal stress, and the maximal shear stress of trough value and normal stress both conform basically to Mohr-Coulomb rule; the maximal shear strength under cyclic load decreases with the increasing of frequency, but increases with amplitude increasing; the shear strength under cyclic load fluctuates with shear displacement, but is always in between the upper and lower boundaries defined by the shear stress under corresponding static normal stresses, the specific quantitative relationship among these related physical variables needs further researches.