Shear Mechanism of Non-Persistent Notches Using Punch Shear Test

Abstract

Experimental and discrete element methods were used to investigate the effect of non-persistent notch angle on the shear behavior of joint’s bridge area. A punch-through shear test was used to model the gypsum cracks under shear loading. Gypsum samples with dimension of 150 × 150 × 50 mm were prepared in the laboratory. Within the specimen model and near the one edge, two notches were provided. Six different configuration systems were prepared for notches. In these configurations, the length of notches was taken as 2 cm. Assuming a plane strain condition, special rectangular models were prepared with dimensions of 100 × 100 mm. Similar to those for joints configuration systems in the experimental tests, i.e. six models with different rock bridge lengths and rock bridge joint angle were prepared. The axial load was applied to the punch through the central portion of the model. This testing showed that the failure process was mostly governed by the notch angle. The shear strengths of the specimens were related to the fracture pattern and failure mechanism of the discontinuities. The failure pattern and failure strength are similar in both methods, i.e. the experimental testing and the numerical simulation methods.