Evaluation of Rock Burst Propensity and Rock Burst Mechanism in Deep Phosphate Mines: A Case Study of Sujiapo Phosphate Mine, Hubei Province, China

Table 3

Set of factors for each rock sample judging object.

Set Z	Each evaluation factor Zi set
	Phosphorite		Dolomite		Shale
	K-1	K-4	D-1	D-2	d-1	d-4
Z 1 (rock strength brittleness factor B)	14.28	17.37	31.70	57.94	26.27	28.79
Z 2 (rock deformation brittleness factor Ku)	4.26	5.84	7.45	6.67	4.72	3.78
Z 3 (barton criterion α)	4.93	5.60	8.82	16.12	9.60	10.52
Z 4 (energy conservation criterion )	6.54	14.07	20.67	37.82	18.65	22.52