Fracture test and Failure mechanism of rock-like material on the term of different relatively fracture apertures

• 1、School of Resource and Safety Engineering, Central South University

Abstract：In the system of uniaxial loading with servo control, a loading test on the rock-like samples with a horizontal fissure was made to explore wreck mechanism with rapture of rock-like materials with single-pressure, by in-deep analysis of the experimental progress and phenomenon, and combining with the results of numerical analysis. For the description of fracture morphology, the concept of relative open degree-b- was introduced, and its value was equal to the ratio of fracture apertures with fracture length. According to the result of experiment and numerical analysis, it shows that: b=0.005 can be set as the cut-off point. Over and under this value, there were two different kinds of failure model, tip yield damage and central tension damage of crack respectively. When b is smaller, we can get the stress intensity distributing in the neighborhood of crack tips basing on the formula of the stress field, but we should do the strength–reduction with the theoretical value calculated according to the theory of linear elastic fracture mechanics. While b is bigger, the failure of cracked sample started from the appearance of micro-crack, which was made by the transverse tensile in the middle of the horizontal crack. In this case, the linear elastic fracture mechanics is not applicable.

Keywords： Relatively fracture apertures Rock-like material Horizontal crack Fracture failure mechanism Linear elastic fracture mechanics