Evaluation on the Stability of Vertical Mine Shafts below Thick Loose Strata Based on the Comprehensive Weight Method and a Fuzzy Matter-Element Analysis Model

Table 6

Standard range of stability evaluation indexes of shafts below thick loose strata.

Evaluation index	Indicator type	Safe	Safer	Critically safe	Dangerous	Extremely dangerous
1	Positive indicator	0~14	14~28	28~42	42~56	56~70
2	Positive indicator	0~110	110~220	220~330	330~440	440~550
3	Positive indicator	0~125	125~250	250~375	375~500	500~625
4	Positive indicator	0~16	16~32	32~48	48~64	64~80
1	Negative indicator	1.6~1.9	1.3~1.6	1.0~1.3	0.7~1.0	0.4~0.7
2	Positive indicator	0~0.2	0.2~0.4	0.4~0.6	0.6~0.8	0.8~1
3	Positive indicator	0.6~0.65	0.65~0.7	0.7~0.75	0.75~0.8	0.8~0.85
4	Positive indicator	0~2	2~4	4~6	6~8	8~10