Burst Failure Characteristics and Energy Evolution Law of Coal with Prefabricated Cracks at Different Angles

Table 2

Uniaxial compressive strength of coal under different crack angles.

Specimen types	Group a (MPa)	Group b (MPa)	Group c (MPa)	Average value (MPa)
Complete cylinder	17.97	21.01	20.4	19.79
0° cracked cylinder	10.86	9.22	10.53	10.2
30° cracked cylinder	10.89	11.66	10.19	10.91
60° cracked cylinder	15.95	13.1	10.85	13.3
90° cracked cylinder	17.68	17.51	23.01	19.4