Uniaxial Compression Creep Relaxation and Grading of Coal Samples via Tests on the Progressive Failure Characteristics

Table 2

Test results of the uniaxial compression step relaxation tests.

Coal number	Progression	/10^−3	/MPa	/%	t/s	/MPa	/10^−3
MZ4	①	4.26	13.07	49	603	0.18	0.00
	②	4.87	15.57	59	692	0.12	0.00
	③	5.51	18.11	68	573	0.11	0.04
	④	6.15	20.64	78	642	1.30	4.28
	⑤	7.26	23.44	89	555	1.10	2.37
	⑥	8.18	26.46	100	589	4.98	16.68
	⑦	9.04	21.00	79	128	5.47	3.40
MZ5	①	5.82	10.15	84	587	0.17	4.65
	②	6.62	11.74	94	590	0.90	12.85
	③	7.61	6.92	57	587	5.80	10.95
MZ6	①	3.11	10.43	38	577	0.07	0.00
	②	3.85	13.04	48	594	0.04	0.00
	③	4.50	15.56	57	572	0.12	0.00
	④	5.17	18.25	67	545	0.08	0.05
	⑤	5.79	20.85	76	549	0.11	0.04
	⑥	6.48	23.58	86	535	0.64	0.14