Crack Initiation, Propagation, and Coalescence Experiments in Sandstone Brazilian Disks Containing Pre-Existing Flaws

Figure 9

Experimental results of crack propagation and coalescence in specimens with different types of pre-existing crack systems. (a) Forward echelon crack system. (b) Inverse echelon crack system. (c) Two parallel cracks. (d) Three parallel cracks. (e) Crack system with barrier cracks.

(a)

(b)

(c)

(d)

(e)