软岩隧道水平收敛异常段支护结构优化研究  

Research on Optimization of Supporting Structure of Soft Rock Tunnel in Abnormal Horizontal Convergence Section

作　　者：黄尚锦[1] 叶欣欣[1] 沙龙 HUANG Shang-jin;YE Xin-xin;SHA Long(CCCC First Highway Consultants Co.Ltd.,Xi’an,710075,China;Zhaotong Transportation Construction Project Quality and Safety Supervision Bureau,Zhaotong 657000,China)

机构地区：[1]中交第一公路勘察设计研究院有限公司,西安市710075 [2]昭通市交通建设工程质量安全监督局,昭通市657000

出　　处：《公路》2022年第5期272-276,共5页Highway

摘　　要：九绵高速青龙桥隧道进口段围岩主要为炭质板岩夹薄层灰岩,岩体极破碎。基于CD法施工存在工效较低的问题,施工单位提出三台阶法施工以加快施工进度。隧道施工过程中,中台阶开挖完成后,部分区段初期支护水平方向收敛异常,局部有拱顶掉块现象,对隧道结构安全和洞内施工安全影响极大。针对现场情况,采用数值模拟方式分析施工存在的问题,同时对增设临时仰拱、加强缩脚锚杆等措施进行模拟,分析支护结构变形规律。通过现场实测数据验证,建议采用三台阶法施工时增设临时仰拱和加强缩脚锚杆。研究成果为该项目后续区段施工提供了有效解决方案,可为类似项目提供参考和借鉴。The surrounding rock at the entrance section of the Qinglongqiao Tunnel of the Jiuzhaigou-Mianyang Expressway is mainly carbonaceous slate with thin limestone, and the rock mass is extremely broken. Due to the low efficiency of the CD method, the construction contractor proposes to use three steps to optimize the construction process. During the tunnel construction process, after the mid-step excavation is completed, the initial support shows abnormal signs of horizontal convergence, and the vaults of some sections fall in blocks, which greatly threaten the safety of the tunnel structure and the safety of the construction in the tunnel. In view of the site situation, in this paper numerical simulation analysis is carried out to analyze the existing problems in the construction, and at the same time the measures of adding temporary inverts and strengthening the anchors with reduced feet are simulated to analyze the deformation law of the supporting structure. Through the verification of on-site measured data, it is recommended to adopt the three-step excavation to add temporary invert and strengthen the foot-reduced anchor.The research results can provide effective solutions for the construction of the subsequent sections of this project, and provide reference for similar projects.

关 键 词：极软岩隧道 水平收敛 临时仰拱 施工安全 

分 类 号：U455.7[建筑科学—桥梁与隧道工程]