Influence of matric suction and counterface roughness on shearing behaviour of completely decomposed granitic soil and steel interface
School of Engineering
The interface can be defined as the zone in which the transfer of stresses occurs between soil and structure. The behavior interface is significantly influenced by stress state variables. In this paper, the influence of matric suction and counterface roughness on the interface shearing behavior was examined by conducting a series of suction controlled direct shear test on the interface formed between completely decomposed granite soil and steel specimens. Experimental tests were performed on two different types of soil–steel interfaces under different stress state variables. Test results show that matric suction has a significant influence on the interface shear behavior. The counterface roughness influences the dilative-contractive behavior of the interface. The critical interface shear strength at specific counterface roughness and net normal stress is controlled by the matric suction. The experimental results are compared with an analytical model that considers the influence of suction and dilation on apparent interface friction angle. The analytical model works reasonably well for predicting the unsaturated soil–steel interface shear strength under different stress state variables.