川藏铁路廊道板块缝合带对软岩分布的控制效应及其工程影响  

CONTROL EFFECTS OF SUTURE ZONES ON DISTRIBUTION OF SOFT ROCK AND ITS ENGINEERING INFLUENCE ALONG SICHUAN-TIBET RAILWAY CORRIDOR

作　　者：易树健 崔鹏[1,2,3] 伍纯昊 李渝生 YI Shujian;CUI Peng;WU Chunhao;LI Yusheng(Key Laboratory of Mountain Hazards and Surface Process,Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,China;University of Chinese Academy of Sciences,Beijing 100049,China;CAS Center for Excellence in Tibetan Plateau Earth Sciences,Beijing 100101,China;State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]山地灾害与地表过程重点实验室,中国科学院、水利部成都山地灾害与环境研究所,成都610041 [2]中国科学院大学,北京100049 [3]中国科学院青藏高原地球科学卓越创新中心,北京100101 [4]地质灾害防治与地质环境保护国家重点实验室(成都理工大学),成都610059

出　　处：《工程地质学报》2021年第2期275-288,共14页Journal of Engineering Geology

基　　金：第二次青藏高原科学考察研究(资助号:2019QZKK0906);国家自然科学基金重点项目(资助号:41941017);中国科学院前沿科学重点研究项目(资助号:QYZDY-SSW-DQC006)。

摘　　要：软岩长期以来都是工程建设中重点关注的对象,在具有高地应力、高温、高水压等复杂环境特点的川藏铁路廊道更是不可忽视的难题,但目前区域软岩的发育分布特征及其工程效应还未有深入的研究。本文在铁路廊道及邻区地质填图成果的基础上,结合岩体结构调查、岩石回弹测试以及微观分析,发现缝合带对软岩发育有着明显的控制效应。取得如下认识:(1)铁路廊道发育金沙江、澜沧江、怒江及雅鲁藏布江等板块缝合带,受缝合带特殊的构造活动形式与温压条件等影响,泥岩、片岩、板岩等软弱岩石及糜棱岩、碎裂岩和损伤岩带等构造软岩主要分布在缝合带内部及其边界断裂两侧;(2)板块碰撞运动控制了区域岩石建造特征,并造成岩石变形变质和构造损伤,使得岩石力学性质劣化,导致区域内软岩广泛发育;(3)川藏铁路廊道软岩工程地质问题主要有受缝合带控制的软弱岩石区段隧道工程大变形风险较高,隧道工程穿越缝合带活动性边界断裂构造软岩时易出现突水突泥灾害,软岩发育且外动力作用强烈的区段频发的山地灾害将严重威胁地表线路及临辅工程。本研究成果可为川藏铁路廊道软岩工程地质问题的预测及防治提供科学依据,也能为板块碰撞挤压作用下软岩的变形机制和工程防控技术等方面研究奠定基础。The Sichuan-Tibet railway corridor has high crustal stress,temperature and water pressure.The soft rock is a difficult problem that cannot be ignored.However,the distribution characteristics and engineering effects of the soft rock have not been deeply studied.This paper is based on the geological map of railway corridor,rock mass structure investigation and rebound test as well as microanalysis.It finds that suture zones had obvious control effect on the formation of soft rocks.The paper has the following findings.(1)There are Jinshajiang,Lancangjiang,Nujiang and Yarlung Zangbo suture zones along Sichuan-Tibet railway corridor.Under the influence of the special tectonic activity pattern,temperature and pressure conditions in the suture zone,the soft rocks such as schist,slate,mylonite,cataclasite and damaged rock zones are mainly distributed in the suture zone and on both sides of the boundary faults.(2)The tectonic damage,deformation and metamorphism of rock mass were caused by the plate splitting and converging movement,which led to the deterioration of rock mechanical properties and form soft rocks in the area.(3)The large deformation risk of railway tunnel engineering is higher in the soft rock section controlled by suture zone.Water and mud inrush will be easy to occur when the tunnel engineering passes through tectonic soft rocks near the active bound faults of suture zone.Besides,mountain hazards in suture zones mainly occur in soft rock area with intense river erosion.These findings can provide scientific basis for the prediction and prevention of engineering geological problems of soft rocks along Sichuan-Tibet railway corridor,and also lay foundation for the research of deformation mechanism and engineering prevention technology of soft rock under plate collision and compression.

关 键 词：川藏铁路 板块缝合带 软岩 工程效应 

分 类 号：P642[天文地球—工程地质学]