INTERACTION OF MULTIPLE CRACKS AND FORMATION OF ECHELON CRACK ARRAYS

Fracturing of rock under compression is a product of a series of processes, including nucleation, growth, interaction and coalescence of multiple microcracks. The formation of echelon arrays of microcracks and macrocracks is one of the crucial rings in the processes. We use a superposition and aymptotic approximation technique to analyse the interaction of multiple cracks with various geometrical configurations. It is shown that crack geometry has a strong influence on crack interaction. Echelon crack arrays produce the strongest interaction and are the prefered geometrical configuration for multiple cracks prior to the formation of through-going shear fractures. This technique provides parameter-dependent global behaviour, and is more efficient and easier to use.