偏压隧道洞口进洞方式实践与探讨

在山岭公路工程建设过程中,选线不可避免地会穿越陡斜山体,在这些位置修建隧道,洞口极可能出现偏压的情况;在偏压段采取何种既安全、又快速、经济和环保的进洞方式,值得思考和探索。以云南公路部分隧道的洞口处理方式为例,列举成功实践的4种类型典型实例进行探讨。从实例及实践结果表明:针对分离式隧道明挖,明洞暗做、护拱盖挖,反压回填、暗挖进洞3种工法各有其优缺点和相应的适用条件;针对连拱隧道当地形偏压、两幅洞口前接构筑物不同(不对称)时,提倡采用错台式洞门进行处理。所述的几种偏压洞口处理方式及分析结论,可为类似工程所借鉴和参考。

Practice and Discussion on Methods for Tunnel Entrance under Asymmetrical Load

In the construction process of mountain highway,the route is often inevitable to pass through steep and inclined mountain. Moreover,if tunnels are located in such area,the tunnel entrance might be subject to asymmetrical load. It is necessary to look for methods to allow entering into the tunnel in a safe,rapid,economical and environmental protecting manner. With reference to the treatment methods employed for Yunnan highway tunnels,this paper proposes four typical examples for discussion. The results show that,for separated tunnel,the three construction methods( open-cut method,cap and excavation method,back pressure & back fill method) have their respective advantages,disadvantages and applicable conditions; for multiple-arch tunnel, in case of asymmetrical load with different structures,stagger portal is recommended. The treatment methods and analysis conclusions introduced in this paper may provide reference for other similar projects.