Effect of the Double-Line Spiral Tunnel Curvature on the Tunnel Construction Stability

Table 2

Different curvature radius of the tunnel alignment for numerical simulations.

Model no.	Curvature radius of left line-RL/m	Curvature radius of right line RR/m	Center line radius of two line-R/m
1	103	141	122
2	203	241	222
3	303	341	322
4	403	441	422
5	503	541	522
6	603	641	622
7	703	741	722