A Study of Safety Coefficient Determination and Support Parameter Optimization Based on Vulnerability Preevaluation

Table 25

Relevant parameters of tailgate N1303.

	Parameters	Value	Dimension
Parameters of surrounding rock	Cohesion	0.4	MPa
	Internal friction angle	21	(o)
Section size	Width	5000	mm
	Height	3600	mm
Bolt support parameter	Length	2400	mm
	Strength	335	MPa
	Diameter	22	mm
	Column spacing	800	mm
	Row spacing	800	mm