摘要
山岭隧道工程在穿越断层构造带时,由于受主次断层叠加断错影响,岩体多表现为结构碎散、软硬不均的特征,在开挖应力释放与地下水渗流的条件下易产生向临空面的变形破坏。高速公路隧道多为扁平化、大断面,不利于开挖过程中围岩应力的协调均匀释放,在深埋条件下穿越宽大断层构造带时,更易引发围岩变形破坏的施工地质问题。某高速公路深埋隧道穿越由多条断层共同组成的断层构造复合带时,在依据超前地质预报成果及时调整围岩级别并预先制定围岩变形破坏防控措施的前提下,围岩仍旧发生了涌水突泥、拱顶坍塌、围岩大变形等较严重的隧道围岩变形破坏。通过对该断层构造复合带内隧道围岩的地质追踪与变形监测数据分析,发现扁平化、大断面高速公路深埋隧道在穿越断层构造带时围岩大变形往往表现为“变形速度快、稳定时间长、下沉较位移更突出、双峰型间断累进式”的特征。同时,将控制该段隧道围岩变形破坏的影响因素归纳为:构造分带性、应力状态变化、地下水作用、开挖支护参数等具有一定普适性的4个方面。另外,通过对该段隧道在围岩变形破坏防控中采用的各类技术措施的适用性与效果分析及归纳,总结并提出了扁平化、大断面高速公路隧道穿越断层构造带的围岩变形破坏防控措施建议,为类似条件下的隧道开挖及支护提供了工程经验与技术借鉴。
When mountain tunnel project crosses fault structural zone, due to the superposition and dislocation of primary and secondary faults, the rock mass in the fault structural zone is mostly characterized by structural fragmentation, uneven hardness and softness. It is easy to deform and damage to the free face under the conditions of excavation stress release and groundwater seepage. The tunnels on expressway are mostly flat and large in section, which is not conducive to the coordination and uniform release of surrounding rock stress during excavation. When crossing wide fault structural zone under deep buried condition, it is easier to cause the construction geological problem of surrounding rock deformation failure. When a deep-buried tunnel on an expressway passes through a fault structure composite zone composed of multiple faults, on the premise of timely adjusting the grade of surrounding rock and formulating prevention and control measures according to the result of advanced geological prediction, serious deformation and damage of surrounding rock such as water gushing and mud inrush, vault collapse, large deformation of surrounding rock and so on still occurred. Through the geological tracking and analysis on deformation monitoring data of the tunnel surrounding rock in the fault structure composite zone, it is found that the large deformation of the surrounding rock often shows the characteristics of “fast deformation speed, long stability time, more prominent subsidence than displacement, and double-peak discontinuous progression” when the flat and large sectional deep-buried tunnel on expressway crosses the fault structural zone. At the same time, the influencing factors controlling the deformation and failure of the abovementioned tunnel surrounding rock are summarized into 4 aspects with universal applicability: structural zoning, change of stress state, groundwater action, excavation and support parameters. In addition, through the analysis and induction of the applicability and effect of various technical measures used in the prevention and control of surrounding rock deformation and failure, the suggestions on the prevention and control measures of surrounding rock deformation and failure of flattened and large sectional expressway tunnel crossing fault structural zone are summarized and put forward. It provides engineering experience and technical reference for tunnel excavation and support under similar conditions.
作者
杨晓芳
李玉倩
吴金刚
YANG Xiao-fang;LI Yu-qian;WU Jin-gang(BGI Engineering Consultants Ltd.,Beijing 100038,China;Beijing Geological and Mineral Exploration and Development Corporation,Beijing 100055,China;Beijing General Municipal Engineering Design&Research Institute Co.,Ltd.,Beijing 100082,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2022年第6期103-110,118,共9页
Journal of Highway and Transportation Research and Development
关键词
隧道工程
防控措施建议
变形破坏分析
断层构造带
影响因素
tunnel engineering
suggestion on prevention and control measures
deformation failure analysis
fault structural zone
influencing factor
