Experimental investigation of cracks pattern effect on the failure of rock-like materials under uniaxial compression loading

Author

Assistant Prof. Shahrood University of Technology

Abstract

Under various loads, pre-existing cracks (flaws) in rock propagate and leads to crack coalescence and failure. In this paper, crack propagation and coalescence mechanism in rock-like materials (gypsum specimens), containing two inclined and open flaws (pre-existing cracks) under uniaxial compressive loads are experimentally investigated. The cubic specimens are prepared from the mixture of gypsum and water and the flaws are created by inserting steel shims into modeling material in the mould template. A set of specimens containing two inclined flaws with the fix length of 15 mm, inclination of 45 degree and connection line of 20 mm with various bridge angle of 45, 60, 75, 90, 105 and 120 degrees are subjected to compressive loads and the mechanical behavior of them are monitored. The bridge angle has important role and controls the propagation and coalescence pattern. For different bridge angles, four coalescence modes including shear, shear-tension, tension - shear and tension mode were observed. With the increase of bridge angle, the corresponding coalescence stress increases.

Keywords