特大跨度隧道Ⅳ级围岩施工方法研究  

Study on Ⅳ Surrounding Rock Construction Method of Super-long Span Tunnel

作　　者：刘旭东[1] Liu Xudong(China Railway First Bureau Group Xiamen Construction Engineering Co.,Ltd.,Xiamen 361000,China)

机构地区：[1]中铁一局集团厦门建设工程有限公司,福建厦门361000

出　　处：《市政技术》2021年第8期60-66,180,共8页Journal of Municipal Technology

基　　金：厦门市建设局科技项目资助(2020-1-21)。

摘　　要：为了解CRD工法对Ⅳ级围岩段特大跨度隧道结构的影响规律,以牛寨山隧道工程为例,借助FLAC3D程序构建精细化三维模型,全过程模拟开挖工序,分析隧道围岩应力、初期支护应力、二次衬砌应力、隧道变形规律等。计算结果表明:隧道开挖后,围岩左、右两侧边墙出现压应力集中区,施工过程中应防止拱顶围岩出现掉落塌落;先期施工的初期支护受力明显大于后期施工的初期支护;二次衬砌最大拉应力、最大压应力均出现在拱顶和左侧边墙;围岩塑性区分布在隧道周边2~8 m范围内,隧道两侧拱脚及边墙底部位置塑性区较深,约为5~8 m厚。最后结合监测数据进行分析,隧道结构安全稳定,表明采取CRD工法施工方案合理。In order to know the influence law of CRD construction method on the structure of super-long span tunnel in grade Ⅳ surrounding rock section, Niuzhaishan tunnel is taken as an example. A refined three-dimensional model is constructed by FLAC3 D program to simulate the whole excavation process. The surrounding rock stress, initial support stress, secondary lining stress, deformation laws of the tunnel are analyzed. The results show that: after the tunnel being excavated, the left and right side walls of the surrounding rock have a compressive stress concentration area, the vault surrounding rock should be prevented from falling and collapsing during the construction process;The stress of initial support structure in early construction is significantly greater than that in later one;Both the maximum tensile and compressive stress of the secondary lining appear at the vault and the left side wall;The plastic zone is distributed within 2~8 m around the tunnel. The plastic zone at the bottom of the arch foot and side wall of both sides of the tunnel are deep, about 5~8 m thick. Combined with monitoring data, the tunnel structure is safe and stable. The scheme daopted CRD construction method is reasonable.

关 键 词：CRD工法 特大跨度隧道 Ⅳ级围岩 数值模拟 现场监测 

分 类 号：U455.4[建筑科学—桥梁与隧道工程]