Severe deformation occurred at the siluric stratum at the ridge of Wushaoling Tunnel, causing splitting of primary lining and even exceeding clearance limit.
乌鞘岭隧道岭脊段志留系地层千枚岩夹板岩地段，施工中发生大变形，初期支护开裂破坏甚至侵限。
2
Based on gray system, programming the software, which can be used to forecast the final clearance displacement of tunnel according to some data of monitoring, named GM-TUNNEL.
根据灰色理论编写了围岩收敛位移的预测程序GM - TUNNEL，预测收敛位移测试点的最终收敛位移。
3
Small clearancetunnel is a tunnel form between separated tunnel and multi-arch tunnel. It is much easier to construct, waterproof and control the cost.