Performance of Super-Large-Span Tunnel Portal Excavated by Upper Bench CD Method Based on Field Monitoring and Numerical Modeling

Table 3

Primary supporting internal force and material safety factor.

Number	Position	Shotcrete axial force (kN)	Steel rib axial force (kN)	Steel rib moment (kN·m)	Safety factor of concrete	Tensile safety factor of steel rib	Compressive safety factor of steel rib
0	Arch	1087	206	−1	6.2 (compression)	12.8	8.8
1	30° left of center of arch	1780	331	−0.1	3.8 (compression)	—	6.4
2	30° right of center of arch	1617	290	0.7	4.2 (compression)	6.8	8.2
3	60° left of center of arch	2472	479	−1.5	2.7 (compression)	5.1	4.3
4	60° right of center of arch	2306	430	0	2.9 (compression)	5	5
5	Left arch foot	1855	366	−2.6	3.7 (compression)	8.2	4.6
6	Right arch foot	1111	178	−8.2	4.9 (tensile)	—	4.2
7	Left side wall	647	147	−5.3	8.9 (compression)	—	6
8	Right side wall	585	178	−8.2	4.1 (compression)	14.2	4.2
9	Left invert	241	47	−0.2	28.1 (compression)	—	38
10	Right invert	235	47	−0.5	28.8 (compression)	—	32.4
11	Invert	104	18	0.4	63.3 (compression)	—	53.2