大跨度隧道塌方处理技术

研究目的：大跨度隧道洞口地形地质情况复杂，围岩完整性差，易出现塌方，对隧道施工进度和质量影响较大，本文结合大丽线禾洛山隧道出口段塌方的处理，对复杂地形地质情况下大跨度隧道洞口段的施工进行总结。 研究方法：针对禾洛山隧道出口段的地形、地质条件以及塌方情况，采用工程类比、数据分析和优化方案的方法，确定经济合理的处理措施，并对围岩、结构变形等进行了量测和分析，对主要结构进行了必要的检算。 研究结果：针对禾洛山隧道出口段具体的地形、地质以及塌方情况，采取有效的处理措施，取得了良好的效果。 研究结论：大跨度隧道洞口段地形、地质情况复杂，围岩软弱，有效预防和处理隧道塌方，顺利通过洞口段是隧道施工成败的关键。本工程采用大管栅、小导管注浆联合超前支付、预留核心土开挖塌体的处理方法，使塌方得到了有效控制和处理，保证了安全顺利通过塌方段，解决了隧道施工进洞难的问题。

Technology for Treating Collapse of Large Span Tunnel

Research purposes:Large span tunnel is easy to collapse because of its complicated geological conditions at the tunnel opening and bad integration of wall rock which generate much influences on construction procedure and quality.In combination with the treatment of collapse of outlet of Heluo Mountain Tunnel on Dali-Lijiang Railway,the summary is made for construction of large span tunnel under complicated geological conditions.Research methods:According to the landform and geological conditions and collapse situation of outlet of Heluo Mountain Tunnel,the economic and rational treatment measures were decided by adopting the methods of comparing similar constructions,data analyses and optimising programs,and survey and analyses were made for the wall rock and structure deformation,including doing necessary verifications for the main structures.Research results:According to the landform and geological conditions and collapse situation of outlet of Heluo Mountain Tunnel,the effective measures were taken and good treatment result was obtained.Research conclusions:For construction of large span tunnel with the conditions of complicated landform and geology and weak wall rock,effective prevention and treatment of collapse and smooth engineering at tunnel opening were the key points for successful tunnelling.The big pipe fence and small pilot pipe grouting were adopted along with remaining core soil for excavation in advance in this construction,so collapse was controlled and treated effectively,engineering succeeded in collapse section and the hard problem in tunnelling was solved.