岩溶地区隧道浅埋段下穿既有构筑物处理技术

Treatment Technology for the Shallow Buried Sections of Tunnel Under-passing Existing Structures in Karst Areas

研究目的:随着高速铁路发展,路网密度增加,铁路选线不可避免会下穿高速公路、地方道路或厂房、民房等不可拆除的地表构筑物。当岩溶发育地区铁路采用隧道形式下穿通过既有构筑物时,可能会揭穿隧道范围内的溶腔或岩溶管道,造成充填物流失或松动,给地表构筑物带来潜在性危害,进而可能影响生产、生活安全。本文结合成贵铁路大方隧道建设情况,就岩溶地区隧道浅埋段下穿既有构筑物隧道施工方法进行研究,提出能够用于未来类似工程的相关理论依据,以有效降低施工过程中对既有构筑物结构安全的影响,确保既有构筑物的使用功能及结构安全。研究结论:(1)应采取措施避免隧道影响范围的溶腔或岩溶管道内充填物流失或松动;(2)需考虑隧道开挖振动及洞内变形对地表构筑物的影响,采用合理的施工开挖方法;(3)加强与构筑物产权单位的协调沟通,确定构筑物防护要求,采取措施确保隧道施工安全和构筑物安全;(4)本研究结论对岩溶地区类似工程条件下隧道设计和施工具有一定的借鉴意义。

Research purposes： With the development of high speed railway and the increase of density of road network in China nowadays, it＇s inevitable to under - pass certain unbreakable structures during the railway alignment such as the expressway, urban roads, factories, private buildings, etc. In the karst development area, when the railway passes through the existing structures with the form of tunnel, it＇s possible to expose the cavity or karst pipe within the tunnel, which may result in the loss or loosening of the filling material, damage the surface structure potentially and affect the safety of life and production. Based on the construction of Dafang tunnel of Chengdu - Guiyang Railway, this paper studies the construction method of shallow - buried section of tunnel under - passing existing structure in karst area, puts forward relevant theoretical basis that can be used for similar projects in the future, to reduce the structural safety impact on the existing structures during the construction process and ensure the functional and structural safety of the existing structures. Research conclusions： （ 1 ） Measures should be taken to avoid the filling loss or looseness in the cavity or karst pipe of the tunnel. （2） The impact of tunnel excavation vibration and deformation on the surface structures needs to be considered, the reasonable method of excavation should be used during construction. （3） The coordination and communication with the property rights units of structures should be strengthened, to confirm the requirements ofstructure protection, ensure safety of structural and tunnel construction. （4） The research conclusions have certain reference significance for the tunnel design and construction under similar engineering conditions in karst areas.