Mechanical and Deformation Characteristics and Optimization of Support Parameters for Superlarge-Span Tunnel: A Case Study from Laohushan Tunnel

Table 9

Internal force and safety factor of primary support under parameter 2.

Monitoring point	Position	Shotcrete axial force (kN)	Axial force of steel rib(kN)	Steel rib bending moment (kN·m)	Shotcrete safety factor	Steel rib tensile safety factor	Steel rib compression safety factor
0	Crown	510.4	115.2	−7.6	8.1	7.4	3.7
1	Deviated left 30°	1457.3	329.0	−3.9	3.1		3.4
2	Vault deviated right 30°	849.0	191.7	−2.2	5.1		5.9
3	Left hance 60°	1837.6	414.8	−0.8	2.6		3.8
4	Right haunch 60°	1069.3	241.4	−1.8	4.1		5.3
5	Left skewback foot	1349.9	304.7	−2.2	3.3		4.2
6	Right arch foot	780.6	176.2	−4.6	5.5	48.7	4.4
7	Left side wall	189.0	42.7	1.4	21.3	88.2	16.4
8	Right side wall	16.0	3.6	0.4	247.4	118.0	78.9