摘要
以成兰铁路某处大断面隧道为工程背景,采用数值模拟的方法分析了双侧壁导坑法施工过程中隧道围岩变形、应力分布、塑性区扩展以及中间岩柱位移轨迹情况,并提出了针对性的支护对策。研究结果表明,采用双侧壁导坑法施工大断面隧道时:(1)中间岩柱发生塑性破坏,但仍能保持一定的承载能力,作为维护隧道稳定的关键,应加强对中间岩柱的支护;(2)左侧导坑开挖后,应及时采用锚杆支护导坑左帮,适当增大左侧顶角与左侧底角锚杆的支护密度,全断面喷射混凝土与施加钢梁支护,并安装斜支撑钢梁;(3)左右侧导坑开挖过程中,中间岩柱整体向左移动,内部出现离层裂隙,右侧导坑开挖前应通过安装横支撑钢梁对左侧导坑进行补强支护,开挖后应及时施加锚杆、喷射混凝土和钢梁支护;(4)中间岩柱开挖后隧道顶底板塑性区范围较大,应及时采用锚杆支护隧道顶底板并对全断面实施混凝土二衬支护。
Taking one of large-section tunnels of Chengdu-Lanzhou railway as engineering background,surrounding rock deformation,stress distribution,expansion of plastic zone and displacement trajectory of the middle rock pillar during construction process of double side heading method were studied by means of numerical simulation,based on which supporting countermeasures and suggestions were put forward.The study shows that when using double side heading method to construct large-section tunnel:The middle rock pillar will be in plastic destruction state,but can still maintain a certain bearing capacity.Much more attention should be paid to support for the middle rock pillar which is the key factor of tunnel stability.After excavation of left heading,bolts support for left side should be implemented in time,as well as the whole-section shotcrete and steel beam support.Support density of upper and lower parts should be increased properly for bolts,and inclined bracing steel beam should be installed for steel beam support.In the process of excavation of both left and right headings,the middle rock pillar moves to left integrally and has separation fissures in itself.Before excavation of right heading,horizontal bracing steel beam should be installed to left heading for strengthening support,then bolts,shotcrete and steel beam support should be implemented to right heading in time after excavation.After excavation of middle rock pillar,plastic zone in roof and floor is larger,so bolts support for roof and floor should be implemented in time,as well as the second concrete lining support for whole section.
作者
杨景贺
王朋
王晓卿
司林坡
YANG Jinghe;WANG Peng;WANG Xiaoqing;SI Linpo(Coal Mining and Designing Branch,China Coal Research Institute,Beifing 100013,China;Coal Mining and Designing Department,Tiandi Science and Technology Co.,Ltd.,Beijing 100013,China;State Key Laboratory of Coal Mining and Clean Utilization,Belting 100013,China;China Railway Eryuan Engineering Group Co.,Ltd.,Chengdu,Sichuan 610031,China)
出处
《施工技术》
CAS
2019年第1期79-83,共5页
Construction Technology
基金
国家自然科学基金青年科学基金项目(51504136
51774185)
关键词
隧道
双侧壁导坑法
数值模拟
围岩
变形
支护
tunnels
double side heading method
numerical simulation
surrounding rock
deformation
supporting
