特大跨超浅埋地铁隧道下穿天桥过程稳定性控制  

STABILITY CONTROL OF ULTRA SHALLOW-BURIED METRO TUNNEL WITH SUPER LARGE-SPAN IN PROCESS OF CROSSING BRIDGE

作　　者：李栋[1,2,3] 何兴玲 覃乐 康勇[2,4] 周东平 郭臣业 

机构地区：[1]重庆市能源投资集团科技有限责任公司,重庆400060 [2]重庆大学煤矿灾害动力学与控制国家重点实验室,重庆400030 [3]重庆市煤层气开发企业工程技术研究中心,重庆401121 [4]武汉大学动力与机械学院,湖北武汉430072

出　　处：《岩石力学与工程学报》2013年第S2期3636-3642,共7页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金委专项创新研究群体基金项目(50921063);重庆市自然科学基金项目(cstcjjA00002);重庆市科技攻关项目(cstc2012gg-yyjsB90001)

摘　　要：针对重庆花卉园地铁隧道洞室开挖复杂条件,在分析隧道稳定性关键影响因素和数值模拟基础上,提出相应控制措施,并结合现场监测对特大跨超浅埋隧道下穿天桥过程稳定性进行研究。结果表明:(1)特大跨超浅埋隧道开挖后难以成拱,引起地层变形明显,导致2#桥桩累计沉降和沉降速率均超过预警值,需采取相应补偿地层损失措施;(2)隧道偏载现象较明显,且各处等效应力集中对扁平率变化敏感程度不同,拱脚最为敏感,拱顶基本不随之改变而改变;(3)特大跨超浅埋隧道变形主要受各部开挖影响,其中核心土开挖造成的变形占主要部分,两侧上洞开挖造成的变形次之,是重点控制部位;(4)采用双侧壁导坑法并辅以超前小导管注浆、回填注浆及浅孔微震光面爆破等措施能有效控制特大跨超浅埋隧道下穿天桥稳定性。By analyzing the key effect factors of the stability and using numerical simulation for the complex excavation condition of Huahuiyuan metro tunnel,the corresponding control methods were proposed. And the stability of ultra shallow-buried tunnel with super large-span in the process of crossing bridge was investigated based on the monitoring results from excavation site. The results show that:(1) It′s difficult to form an arch after the ultra shallow-buried tunnel with super large-span excavation and the obvious ground deformation caused by the excavation shows skewed which lead to the subsidence of No.2 pile exceeds the warning value. So,some strengthening measures must be taken. (2) The phenomenon of equivalent stress concentration in different parts of the tunnel structure has different sensitivities to the change of flat rate:the most sensitive part is skewback while the equivalent stress concentration in the vault does not change along with the flat rate. (3) The deformations of ultra shallow-buried tunnel with super large-span are mainly influenced by the excavation of each part,in which the dominant deformation is caused by core soil excavation and then by upper hole excavation. As a result,both of them are the key control parts. (4) Both sides heading method assisted by advanced small pipe grouting, backfilling grouting,short-hole micro seismic blasting and so on can control the ultra shallow-buried tunnel with super large-span stability in the process of crossing bridge effectively.

关 键 词：隧道工程 特大跨超浅埋隧道 下穿天桥 稳定性控制 双侧壁导坑法 

分 类 号：U455.4[建筑科学—桥梁与隧道工程]