Numerical Investigation of Influences of Drilling Arrangements on the Mechanical Behavior and Energy Evolution of Coal Models

Table 5

Energy indexes of specimens with different drilling arrangements.

Test scheme	RD (mm)	NH	NR	(%)	(MJ/mm^3)	(MJ/mm^3)
I	3	1	1	1.01	0.1023	0.0112	9.13
	5			3.35	0.0953	0.0121	7.87
	8			24.35	0.0787	0.0110	7.17
	10			41.93	0.0600	0.0150	4.00
II	3	1	1	1.01	0.1023	0.0112	9.13
		2		2.51	0.1008	0.0112	9.00
		3		10.12	0.0929	0.0106	8.76
		4		14.89	0.0890	0.0115	7.74
III	3	3	1	10.12	0.0929	0.0106	8.76
			2	13.36	0.0895	0.0075	11.93
			3	23.71	0.0788	0.0161	4.89
			4	26.17	0.0763	0.0075	10.17