琼州海峡工程地质条件及铁路隧道方案研究

Study of Engineering Geological Conditions and Railway Tunnel Scheme across Qiongzhou Strait

琼州海峡跨海通道不仅仅只是一个交通问题,同时涉及能源、国防、科技、对外开放、综合利用、政治、经济诸多领域,是一项增强我国综合国力、保卫国家领土完整、推动区域经济发展的重大工程,通道的建设具有重要的意义。琼州海峡的建设条件相当复杂,在收集并研究大量有关资料的基础上,对影响海底隧道的地震、地质构造等主要工程地质条件进行分析,进而研究跨海峡的各种方案,认为琼州海峡跨海工程采用隧道方式更优,同时由于公路隧道存在诸多技术难题,推荐采用铁路隧道方案,汽车可通过穿梭列车运行通过隧道。根据海底地形及地质条件,初步设计4条铁路隧道线位方案,并对其进行综合对比分析,得出线位Ⅱ优于其他线位,可为下一步详细的线位比选提供参考。隧道横断面采用2行车隧道+服务隧道的形式,3条隧道的结构型式和尺寸相同,3条隧道均采用盾构法施工。

The cross-sea channel for the Qiongzhou Strait not only provides a solution for transportation,but also plays an important role in the political and economic development of the region.In addition,the project has an extensive impact on many fields,such as energy,national defense,science and technology,opening up and reform,comprehensive utilization and so on.It is a significant project to enhance China′s comprehensive national strength,defend the country′s territorial integrity and promote regional economic development.The geological conditions across the Qiongzhou Strait are complex.A large amount of existing engineering geological information and hydrogeological data are collected,based on which the seismic impact on subsea tunnels and the main geological conditions including tectonic structures are analyzed.Different options crossing the Qiongzhou Strait have been considered and compared in terms of engineering geology,environmental condition,as well as the construction feasibility.The analystical results indicate that a subsea tunnel has more advantages over a bridge.Because more complicated technical difficulties have to be solved for a highway tunnel which would potentially increase construction and operation costs,a railway tunnel scheme is recommended.Vehicles can be carried by trains through the Qiongzhou Strait railway tunnel.Based on the seabed topography and geological conditions,four preliminary railway tunnel routes are proposed.After a comprehensive comparative analysis,the railway tunnel routeⅡis identified to be superior to other alternatives and should be the basis for determining the final tunnel layout.The proposed tunnel cross section includes two railway tunnels and one service tunnel.All the three tunnels have the same structural form and dimension and will be constructed by shield.