Evaluating Long-Term Strength and Time to Failure of Sandstone with Different Initial Damage

Table 6

Creep parameters of rock specimens with different initial damage states.

Creep stress (MPa)	Initial damage	E1 (GPa)	E2 (GPa)	η1 (GPa·h)	η2 (GPa·h)
15.7	D1	14.9	269.5	—	483.8
	D2	15.5	234.6	—	450.3
	D3	14.1	244.9	—	431.1
	D4	14.4	226.5	—	450.5
19.6	D1	12.17	152.76	—	420.25
	D2	12.21	139.19	—	400.32
	D3	11.2	149.64	—	386.91
	D4	11.46	122.55	—	396.91
23.5	D1	10.68	103.61	—	273.68
	D2	10.94	102.62	—	259.52
	D3	10.13	108.66	—	233.65
	D4	10.31	112.66	—	264.41
27.4	D1	9.35	73.68	—	151.02
	D2	9.55	75.11	3773	146.78
	D3	8.98	82.67	3973.64	131.13
	D4	9.16	88.67	3673.64	135.27
29.4	D1	8.38	64.41	2773	123.66
	D2	8.52	60.28	2723	124.12
	D3	8.11	65.69	2873.64	127.97
31.4	D1	7.89	50.13	1973	95.79
	D2	8.01	48.13	1656	85.79