穿越强岩溶地质条件的隧道安全施工初探——以宜(昌)万(州)铁路岩溶一级风险隧道为例

宜万铁路是我国铁路网"八纵八横"主骨架之一,铁路地处云贵高原区与长江中下游平原区的结合部,线路沿线地形复杂,其正线桥隧占线路总长的74%,其中70%的隧道穿越炭酸盐岩岩溶地层,隧道穿越岩溶区施工中存在隧道塌方、突泥、突水等高风险,是典型岩溶隧道灾害区.在宜万线岩溶隧道建设中,针对当前岩溶区隧道施工依然按一般隧道施工步序进行施工,对岩溶隧道灾害了解不深,考虑不全面,施工处于盲目、被动的状态的现状,在对已有岩溶隧道施工调查基础上,结合宜万线26座岩溶风险隧道的施工实践,以施工时间过程(施工前、施工中、施工时和施工后)为主线,提出了岩溶隧道施工的四阶段工作法,论述了不同阶段的工作内容和任务,完善和规范了岩溶区隧道的施工管理.宜万线岩溶隧道施工实践证明了四阶段工作法的有效性和可行性,该方法对经济合理、安全可靠地进行岩溶区隧道的施工具有积极的指导意义.

Preliminary Investigation on Save Construction of the Tunnel Passing through Strong Karst Geology——Taking the Yi-Wan Railway Tunnel with First Class Risk of Karst as Example

Yi-wan railway is one of the key frames of the railway net in China,which is situated in the connec- tion of Yunnan plateau and Yangtze middle and lower reach plain with complicated topography along the line.The bridges and tunnels on the line take 74% of the total length and 70% of the tunnels pass through the carbonate karst stratum.There may be collapse,soil or water outburst in the tunnel in this region,which belongs to the karst tunnel disaster region.However,during the construction of without proper consideration of the possible disaster.Based on in- vestigation of constructed karst tunnels with considering the experinec of 26 tunnels with karst risk at Yi-wan rail- way,a four-stage construction procedure(before,in midway of,in progress of and after construction)was suggested, the content and task for each stage is described and the management is normalized.The practice in karst tunnel con- struetion on Yiwan railway shows that the four-stage construction procedure is effective and feasible and can serve as a guide to safe and rational construction of tunnel in karst region.