Crack Initiation and Propagation of Embedded Three-Dimensional Parallel Cracks in Transparent Rock-Like Material

摘要

In order to understand the initiation and propagation of three-dimensional (3D) embedded parallel cracks in brittle rock under uniaxial and biaxial compression, a preparation method of a transparent rock-like material was proposed in order to observe the propagation process of cracks in brittle rock. Uniaxial and biaxial compression tests were carried out on the transparent rock-like samples containing two embedded 3D parallel cracks. Four types of crack propagation modes were observed: wing crack, petaloid crack, flat-wing crack, and ring-like crack. It is also found that the direction of lateral pressure relative to the strike of the embedded crack has a significant effect on the propagation direction of new generated cracks: a lateral pressure parallel to the strike of the embedded cracks promotes crack propagation in the direction of the maximum principal stress; on the other hand, a lateral pressure normal to the strike of the embedded cracks promotes cracks propagation around the embedded crack at an angle of 30°-60°, forming ring-like cracks, which is similar to the zonal disintegration phenomenon monitored around deep underground excavations.