Experimental Study on the Crack Initiation and Propagation of Unequal Cracks in Rock-Like Materials

Table 4

The statistical table of the test condition A coalescence mode.

Test condition A: Lcd = 24 mm and Lab = 12 mm
	Longer crack propagation	Shorter crack propagation	Initial cracking location	Coalescence mode	Ultimate strength (MPa)
Test condition 1
α = 0°; Lbc = 12	No	No	Specimen side	No coalescence	47.07
Test condition 2
α = 30°; Lbc = 12	Yes	Yes	c and d	Mixed mode	46.28
Test condition 3
α = 45°; Lbc = 12	Yes	Yes	d	Shear mode	36.55
Test condition 4
α = 60°; Lbc = 12	Yes	No	c	No coalescence	36.39
Test condition 5
α = 90°; Lbc = 12	Yes	No	c	Shear mode	36.67
Test condition 6
α = 0°; Lbc = 18	No	No	The lower end of the specimen	No coalescence	48.82
Test condition 7
α = 30°; Lbc = 18	Yes	No	d	No coalescence	48.71
Test condition 8
α = 45°; Lbc = 18	Yes	Yes	c and a	Mixed mode	45.74
Test condition 9
α = 60°; Lbc = 18	Yes	Yes	d and b	Mixed mode	45.45
Test condition 10
α = 90°; Lbc = 18	Yes	No	d	No coalescence	41.54
Test condition 11
α = 0°; Lbc = 24	No	No	—	No coalescence	51.64
Test condition 12
α = 30°; Lbc = 24	No	No	The lower right end of the specimen	No coalescence	51.14
Test condition 13
α = 45°; Lbc = 24	Yes	No	d	No coalescence	42.19
Test condition 14
α = 60°; Lbc = 24	Yes	Yes	d	Mixed mode	43.75
Test condition 15
α = 90°; Lbc = 24	Yes	No	d	No coalescence	37.35