Failure Mechanism and Optimization of Arch-Bolt Composite Support for Underground Mining Tunnel

Table 1

Test schemes.

Scheme no.	Parameters of roadway and support	Vertical ground stress (MPa)	Lateral ground stress coefficient λ
1	Roadway: width 4.4 m, height 3.8 m; Anchor bolt: length 2.2 m, diameter 18 mm, spacing 0.65 m × 0.8 m; CFST arch: square section 150 mm × 8 mm, C40 concrete	2.5	1.0
2		5
3		10
4		15
5		20
6		10	0.5
7			0.75
8			1.0
9			1.25
10			1.5