Effects of Asperity Angle and Infill Thickness on Shear Characteristics Under Constant Normal Load Conditions

Direct shear tests under constant normal loads were conducted to investigate the effects of the asperity angle and the infill thickness on shear characteristics. The results showed that the increase of the asperity angle frequently led to the degraded area, whereas the opposite occurred for the increase of the ratio of asperity height to infill thickness (t/a). In addition, tensile fracture of the asperity occurred for the high asperity angle and the low t/a ratio. On the contrary, shear abrasion prevailed with the small asperity angle and the high t/a ratio. The degradation transition may result from the variation of the effective contact area between two blocks and deserves further studies. It can be further concluded that the asperity angle and infill thickness significantly determine shear characteristics of the infilled joint. For joints with thick infill materials, the improvement of the mechanical properties of the infill will contribute to promoting the shear strength.