Propagation process analysis of I type fracture on non-uniform rock based on internal motive force

Natural rock material of different mineral composition contains holes, cracks, and other surface microstructure, is the non-uniform materials of composition and structure. The rock damage on loading is mainly due to this non-uniform. Authors introduced the concept of the internal motive force, analyzed the fracture propagation and involution law of the non-uniform rock material. According to the concept of the inside and outside region on the fracture propagation, authors selected the non-uniform structures rock material that was containing pre-crack, a uniform and non-uniform in the area of the material were calculated to analyze the fracture propagation process. The results show that crack propagation is along the pre-crack straight extension and the maximum value of the internal motive force is always at the crack tip and the crack length is the same as each time step when the uniformity material of the inside region rock that is only non-uniform structure; crack propagation is no longer straight but in a zigzag extending, the irregular stress state diagram, extends a certain length after the original crack is no longer along the pre-crack extension, but to generate new cracking point when the inside region material is non-uniform that is the structure and material are both non-uniform. ©, 2015, China Coal Society. All right reserved.