Dynamic interaction of a propagating crack with an oblique fault

Abstract

The behaviour of a fast running crack against an internal oblique fault in a brittle material (polymethylmethacrylate) was investigated by the use of high-speed photography and caustics. This problem is significant in rock mechanics, where the whole failure of the rock mass is often due to such dynamic interaction phenomena during earthquake activities.

Interesting effects were disclosed when the rapidly moving crack was approaching the internal fault. The non-homogeneous stress field, which was created by the internal slant crack, forced the main propagating crack to a curved path, and simultaneously, to a deceleration of its velocity and eventually its arrest, as well as the variation of the only effective K_I-stress intensity factor along almost all the field of propagation of the crack. The purpose of this paper is to investigate the conditions which govern the development of such phenomena.