Cracking Behaviors of Rock-Like Specimens Containing Two Sets of Preexisting Cross Flaws under Uniaxial Compression

Abstract

Cross flaws occur widely in rock masses and play a crucial role in the failure of rock engineering. This article first experimentally studies the cracking behaviors of rock-like specimens containing two sets of preexisting cross flaws under uniaxial compression. The effects of the flaw inclination angle and the horizontal spacing on the cracking behaviors of rock-like specimens are investigated as well as initiation stress, peak strength, peak strain, and complete stress–strain curves. The experimental results include observations of five types of cracks and seven types of coalescence. The crack initiation mode depends more strongly on the inclination angle than on the horizontal spacing. Moreover, it is found that a set of preexisting flaws coalesce not only with another set of preexisting flaws but also with the identical set of preexisting flaws. The peak strength and peak strain first increase and then decrease as the horizontal spacing increases. Meanwhile, the peak strength first increases and then decreases, and the peak strain first decreases, then increases, and finally decreases as the flaw inclination angle increases. This study provides a better understanding of the mechanical properties and fracture behaviors of rock masses, in particular those containing preexisting flaws that appear in sets or groups with similar orientation and characteristics.