西宁至成都铁路特殊地质问题及选线研究  

Research on the Special Geological Problems and Route Selection of the Xining-Chengdu Railway

作　　者：张志亮[1] ZHANG Zhiliang(China Railway First Survey and Design Institute Group Co.Ltd,Xi'an,Shaanxi 710043,China)

机构地区：[1]中铁第一勘察设计院集团有限公司

出　　处：《铁道工程学报》2019年第12期11-16,28,共7页Journal of Railway Engineering Society

基　　金：国家重点研发计划项目“红层地区典型地质灾害失稳机理与新型防治方法技术研究”(2018YFC1504904,2018YFC1504901,2018YFC1504906);国家自然科学基金重点项目“强各向异性岩体开挖弱化机理与强度-刚度主动调控研究”(41831290);铁一院科研项目(院科17-12、16-56)

摘　　要：研究目的:西宁至成都铁路位于青藏高原东北缘,地质条件复杂,不良地质极其发育,并首次面临高压气藏以及红层砂岩水稳性、大范围软岩大变形等特殊地质问题的挑战,需开展针对性的研究工作,优化线路方案,降低工程风险。研究结论:(1)高压气藏为基底大理岩受热分解产生的CO2,受鼻状隆起构造控制,因此线路方案应绕避查明的隆起构造;(2)基于岩性、水文条件的水稳性评价结果表明,白垩系民和组、第三系贵德组等红层砂岩水稳性差,线路应进行绕避或以最小距离通过;(3)基于初始地应力、岩石特征、地下水与隧道轴向等,对潜在大变形风险进行了分析并优化线路方案,最终推荐方案以轻微~中等大变形为主;(4)本研究对存在类似地质问题的铁路、公路等工程的勘察、设计及选线具有借鉴意义。Research purposes:The Xining-Chengdu Railway is located in the northeastern margin of the Qinghai-Tibet Plateau,with complex geological conditions and extremely developed undesirable geology.It is also facing the challenges of high pressure gas reservoir for the first time,and water stability of red sandstone,a wide range of large deformation of soft rock and other special geological problems.Therefore,it is necessary to carry out targeted research to optimize the route scheme and reduce the project risk.Research conclusions:(1)The main components of the high pressure gas reservoir is CO2 which formed from thermal decomposition of basement marble and controlled by nose-like uplift structure,thus the line scheme should avoid the uplift structure.(2)The results of water stability evaluation based on lithological and hydrological conditions show that the water stability of red sandstone strata in Cretaceous Minhe Formation and Tertiary Guide Formation is poor,where the routes should be bypassed or passed at a minimum distance.(3)Based on the initial in-situ stress,rock characteristics,groundwater and tunnel axis,the potential large deformation risk of soft rock is analyzed,and a best route scheme is optimized.The final recommended scheme is mainly slight to medium large deformation.(4)The research result has reference significance for the survey,design and line selection of railways,highways and other projects with similar geological problems.

关 键 词：高压气体 CO2 红层 水稳性 软岩 大变形 西宁至成都铁路 

分 类 号：P642[天文地球—工程地质学]