Fracture growth-II. Case studies

Abstract

SUMMARY Fracture growth under simple shearing, under transtension, and under transpression has been studied with the maximum strain-energy release-rate criterion G,,,. A repulsion scheme is used to handle the friction contact of the fracture faces. Numerical results show that, under simple shearing or transtension, a fracture grows with an abrupt change in orientation (70 with respect to the fracture), and the trajectory of the fracture growth is smooth and slightly convex. These features are in remarkable agreement with laboratory results obtained by many investigators. Under transpression, a fracture also grows with an abrupt change in orientation, and the smooth trajectory of the fracture growth is slightly concave when the compression is large. The interaction of two fractures under shearing is quite different from that under tensile loading. Under left-lateral shearing, when the two right-stepping fractures are far apart, they run away from each other; when they are close, interaction takes place, and they tend to interconnect. Under right-lateral shearing, a pull-apart basin may form by the growth of two right-stepping fractures.