高海拔复杂地层隧道选线方案及工程对策研究

Research on the Scheme of Line Position and Engineering Countermeasures of Tunnel in High Altitude and Complex Strata

研究目的:近年来我国西部铁路建设过程中的高海拔复杂地层问题日渐凸显,广泛分布的三叠系板岩、新近系砂岩地层极大地增加了隧道建设的难度。本文依托西宁-成都铁路甘青隧道,针对高海拔复杂地层中特长隧道选线及工程问题开展研究,针对影响工程建设的瓜什则盆地开展详细的物探和钻探,并构建瓜什则盆地地层分布模型。研究结论:(1)结合本工程地质条件和类似工程经验,确定了线路方案选择原则,从施工难度与风险、辅助坑道设置条件、线路设置条件和工程投资等方面对比分析了不同方案的适应性,结果表明绕避瓜什则盆地高位设隧方案最优;(2)结合工程建设难点,对于隧道修建方案、施工方案、高地应力大变形地层以及膨胀岩地层隧道结构设计等关键工程问题分别进行了研究,并给出了对应的工程措施;(3)本研究成果可为类似复杂地层铁路隧道勘察设计提供参考。

Research purposes:In recent years,the attention has been paid on the problem of complex strata during the process of railway construction in Western China.The widely distributed Triassic slate and Neogene sandstone strata greatly increase the difficulty of tunnel construction.Based on the newly-built Ganqing tunnel of Xining-Chengdu railway as an example,the scheme of line position and engineering countermeasures of super long tunnel in high-altitude complex stratum were studied,and the stratigraphic distribution model of Guashize basin was built based on detailed geological exploration.Research conclusions:(1)According to geological conditions and similar engineering experience,the principle of site selection is proposed.In this study,the advanvement and disadvancement of different schemes are analyzed and compared in many aspects,i.e.,construction difficulty and risk,auxiliary tunnel setting conditions,line setting conditions and project investment,results indicate the bypass scheme is best.(2)Combined with the difficulties in engineering construction,the key engineering problems such as tunnel construction scheme,construction scheme,tunnel structure design in high ground stress and large deformation stratum are studied respectively,and the corresponding engineering countermeasures are proposed.(3)The research results can provide reference for the railway tunnel survey and design in similar complex strata.