Experimental Investigation on Long-Term Strength and Acoustic Emission Characteristics of Coal Pillar under Inclined Compression Loading

Table 1

The UCS of coal specimens under various inclination angles.

Inclination angles		UCS (MPa)	Selected UCS (MPa)	Average UCS (MPa)	Absolute deviation (MPa)	Relative deviation (%)	Standard deviation (MPa)	Relative standard deviation (%)
0°	1#	11.24	/	15.55	/	/	0.288	1.85
	2#	16.07	16.07		0.52	3.3
	3#	15.32	15.32		0.23	1.5
	4#	17.78	/		/	/
	5#	15.26	15.26		0.29	1.9
5°	1#	8.65	/	9.73			0.095	0.98
	2#	9.89	9.89		0.16	1.6
	3#	13.54	/
	4#	9.35	9.35		0.38	3.9
	5#	9.95	9.95		0.22	2.3
10°	1#	7.9	7.9	7.46	0.44	5.9	0.037	0.5
	2#	7.16	7.16		0.3	4.02
	3#	8.9	/
	4#	6.9	/
	5#	7.32	7.32		0.14	1.9
15°	1#	7.5	/	5.82			0.015	0.26
	2#	5.1	/
	3#	5.42	5.42		0.4	6.9
	4#	6.21	6.21		0.39	6.7
	5#	5.83	5.83		0.01	0.2
20°	1#	5.9	/	4.71			0.002	0.04
	2#	3.57	/
	3#	4.89	4.89		0.18	3.8
	4#	4.67	4.67		0.04	0.8
	5#	4.57	4.57		0.14	2.97