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

Table 26

The Comparison of N1303 conveyer tunnel and tailgate N1303.

Technical and economic indicators		Support parameter of N1303 conveyer tunnel	Optimization parameter in tailgate N1303	Difference
Total amount of deformation (mm)	Roof	193	272	+40.9%
	Floor	53	102	+92.4%
	Two ribs	241	326	+35.2%
Average stress during excavation(kN)	Bolt	63.4	98.6	+55.5%
	Anchor	115.6	235.8	104%
Excavation speed (m/d)		6.4	9	+40.6%
Cost (%)		100	74.6	−25.6%