Study on Extension Law of Crack Closing in Rock under Compression
Based on the theory of linear elastic fracture mechanics, formulae for the circumferential stress and the initial fracture point around flattening elliptical hole under compression were derived. When considering the expansion of closed crack under pressure, by introducing the effective friction coefficient f obtained the advantages derived crack angle and the friction coefficient of the crack surface had inversely proportional relationship. Use the software RFPA2D to simulate the rock samples with pre-fracture. The results show that the plane of weakness occurred fracture firstly that lead to the weakness plane through and then formed to be cracks. With the axial displacement exerting, the through crack occurred closure, the end of the rock fracture produced a curved path expansion at the same time. The final destruction face of the rock is approximately a 450 slip-line. It shows that the final failure mode of the rock is compression and shear failure. Different crack angles make the differences of initial cracking angle, but the crack propagation mode and its ultimate failure mode are similar, while have no affect on the carrying capacity.
M. Y. Liu et al., "Study on Extension Law of Crack Closing in Rock under Compression", Applied Mechanics and Materials, Vols. 94-96, pp. 938-943, 2011