川藏铁路拉林段地应力特征及高地应力风险调控选线策略  

CHARACTERISTICS OF MEASURED STRESS AND ROUTE SELECTION STRATEGY UNDER HIGH IN-SITU STRESS RISK CONTROL ALONG LALIN SECTION OF SICHUAN-TIBET RAILWAY

作　　者：黄艺丹[1,2,3] 潘前 姚令侃 陈诺[4] HUANG Yidan;PAN Qian;YAO Lingkan;CHEN Nuo(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;MOE Key Laboratory of High-speed Railway Engineering,Chengdu 610031,China;National Engineering Laboratory for Technology of Geological Disaster Prevention in Land Transportation,Chengdu 610031,China;China Railway Eryuan Engineering Group Co.,Ltd.,Chengdu 610031,China)

机构地区：[1]西南交通大学土木工程学院,成都610031 [2]高速铁路线路工程教育部重点实验室,成都610031 [3]陆地交通地质灾害防治技术国家工程实验室,成都610031 [4]中铁二院工程集团有限责任公司,成都610031

出　　处：《工程地质学报》2021年第2期375-382,共8页Journal of Engineering Geology

基　　金：四川省科技计划项目(资助号:2019YFG0001,2020YFH0056);国家自然科学基金(资助号:41902302);中国科学院国际伙伴计划“一带一路”科技合作项目(资助号:131551KYSB20180042);中铁二院工程集团有限责任公司科研项目(资助号:KYY2020054(20-22));国家重点研发计划资助项目(资助号:2016YFC0802206)。

摘　　要：随着我国铁路向青藏高原等西部山区延伸,长大深埋隧道越来越多,高地应力已成为对线路方案起控制作用的一类复杂地质状况,对其风险以在选线阶段就着手调控最为主动,但前提是能够对隧址区地应力状态定量评估。川藏铁路拉林段地应力实测数据表明,地应力结构以逆断型和走滑型为主;最大主应力方向分布于N19°W~N30°E之间。地应力随埋深分布最重要的规律为:地应力状态转换深度约为500 m,小于该深度时,最大水平应力随埋深变化紊乱,但最大值不超过极高应力量级;大于该深度后,最大水平应力可用海姆公式估算。据此提出:对于埋深小于转换深度的隧道,宜采用施工期动态调整支护结构和施工方法的手段,控制高地应力风险;对于埋深大于转换深度的超深埋隧道,利用隧址区地应力可用海姆公式估计的认识,宜运用选线手段,通过方案经济技术比较择优确定线位。最后建立了高地应力风险调控选线作业程式。研究为破解铁路方案比选阶段缺乏地应力定量评估方法的难题开拓了思路。With the extension of China’s railway to the western mountainous areas such as the Qinghai-Tibet Plateau,there are more and more deep buried tunnels.High in-situ stress has become a kind of complex geological condition which controls the route selection scheme.If it is possible to quantitatively assess the in-situ stress state of the tunnel site before lifting,then the risk control is the most active in the stage of route selection.We have measured a lot of in-situ stress data along the Lalin section of Sichuan-Tibet railway.The structure of in-situ stress in the study area is mainly reverse stress regime and strike-slip stress regime.The direction of in-situ stress is distributed between N19°W~N30°E.The average transition depth of in-situ stress state is about 500 m.Less than that depth,the maximum horizontal in-situ stress has disordered change with buried depth.But the maximum value does not exceed the maximum stress level.More than that depth,the maximum horizontal stress can be estimated approximately by Helm formula.This is the most important rule of in-situ stress with depth.Based on this:If the buried depth of the tunnel is less than the transition depth,the supporting structure and construction method should be dynamically adjusted during the construction period.Because this is conducive to control the risk of high in-situ stress.If the buried depth of the tunnel is more than the transition depth,the in-situ stress of tunnel site can be estimated by Helm formula.According to the understanding,we can use the method of route selection to choose the better scheme of economy and technology.Finally,the route selection program of high in-situ stress area is established.The paper gives useful ideas for solving the problem of lack of quantitative evaluation method of in-situ stress in railway scheme selection stage.

关 键 词：川藏铁路拉林段 高地应力 选线 转换深度 海姆公式 

分 类 号：P315.727[天文地球—地震学]