Comparison of behaviors of soil-concrete interface from ring-shear and simple shear tests

The advantages and disadvantages were pointed out by comparing the apparatus including direct shear apparatus,simple shear apparatus and ring shear apparatus,which are commonly used to study the deformation and strength behaviour of the interface.The deformation and strength behavior of the interfaces between a soil and concrete are investigated by using simple shear test.The interfaces include two types,i.e.interface between soil and concrete,and that of soil-mudcake-concrete.The existing results of ring shear tests from references are employed to compare with those from simple shear tests in this paper;and the differences between them are investigated.The results show that the shear strength measured in simple shear test is smaller about 30%-40% than that found in ring shear test.It is pointed out that the ring shear test is more suitable for studying the strength behavior of interface;and the simple shear test,however,is better for investigating the behavior of stress and strain under lower stress level.The strength of interface decreases about 30% due to the existence of mudcake between soil and concrete.