宜万线隧道工程岩溶治理技术与工程实例

The Technology of Treating Karst for Yichang-Wanzhou Railway and Its Engineering Example

研究目的:宜万线是目前已建和在建工程中岩溶最为发育的铁路线,全线共有隧道159座,约占线路总长度的59%,其中多数隧道穿越碳酸盐岩地层,岩溶、岩溶水极其发育,这给隧道工程的安全施工以及工程建成后的运营安全造成十分重要的影响。研究结论:施工中所遇到的岩溶按工程地质特征分为洞穴型、溶隙溶槽型、管道型、大型岩溶四大类,并按无充填型、半充填型、充填型、充水型、过水型、暗河型等水文地质特征进行次级分类,以便进行针对性治理。根据分类,针对岩溶洞穴型主要采取回填、换填、注浆加固等措施;针对溶隙溶槽型,主要采取护拱回填、加强预支护开挖、注浆加固等措施;针对岩溶管道型主要采取护拱回填、预引排、注浆加固及大管棚预支护、维持原排水通道等措施;针对大型岩溶型,上部主要采取护拱回填、注浆加固及大管棚预支护,基底主要采取钢管桩、板跨、梁跨、桩基承台、回填路基等措施。

Research purposes： Yichang- Wanzhou railway is the railway in the mostly developed karst area. There are 159 tunnels on the railway line, which covers 59% of total line length and most of them are in the area of carbonate rock stratum with karst and rich karst water. Therefore, it will make big influences on the safe construction of tunnels and tunnels＇ operation in future. Research conclusions：The karsts encountered in the construction can be divided into four types according to the engineering geological characteristics, namely cave type, fluid bowl type, pipe type and large - sized karsts, and they can be divided further according to the hydro - geological characteristics, namely free filling type, semi - filling type, filling type, flow type, overflow type and underground river type. For the kasrst cave, the reinforcing measures of filling, refilling and grouting can be taken, for fluid bowl, the reinforcing measures of filling guard arch, supporting the excavated area and grouting can be taken, for the karst pipe, the reinforcing measures of filling guard arch, drainage in advance, grouting, support with large pipe shed and remaining the existing drainage system can be taken, and for large - sized karst, the reinforcing measures of filling guard arch, grouting and support with large pipe shed can be taken for the upper and steel pipe pile, slab and beam crossing the tunnel, cap of pile trestle and filling subgrade can be taken for the bottom.