膨胀岩地层双线隧道仰拱矢跨比对二次衬砌力学特性的影响  

Influence of Rise-Span Ratio of Double Track Tunnel Inverted Arch on Mechanical Properties of Secondary Lining in Swelling Rock Stratum

作　　者：符亚鹏[1] FU Yapeng(China Railway First Survey and Design Institute Group Co.Ltd.,Xi an Shaanxi 710043,China)

机构地区：[1]中铁第一勘察设计院集团有限公司,陕西西安710043

出　　处：《铁道建筑》2018年第8期64-66,共3页Railway Engineering

摘　　要：膨胀岩水敏感性强,遇水膨胀变形,而传统的隧道排水系统不能给仰拱下方地下水提供通畅的排出通道。基于荷载-结构设计理念,采用有限元软件构建二维数值计算模型,分析了不同仰拱矢跨比下隧道二次衬砌弯矩、轴力及安全系数的变化规律。结果表明:仰拱矢跨比对仰拱和边墙二次衬砌力学特性影响大,对拱部影响小;随着仰拱矢跨比的增大,仰拱、边墙处二次衬砌弯矩减小,仰拱处二次衬砌轴力增大,墙脚处二次衬砌轴力减小,仰拱、边墙处二次衬砌安全系数均增大;仰拱矢跨比为1/11.87时墙脚处安全系数小于2,不满足规范要求,因此膨胀岩地层隧道设计应适当提高仰拱矢跨比。Swelling rock which is sensitive to water will appear expansion and deformation with water,and the conventional tunnel drainage systems can t provide unobstructed drainage of groundwater under the inverted arch.The two dimensional numerical calculation models were established based on the load-structure design concept by using the f inite element software,and the change law of the bending moment,axial force and safety coeff icient of the tunnel secondary lining with the different rise-span ratios of the inverted arch was analyzed.The results show that the rise-span ratio has a great inf luence on the secondary lining mechanical properties of the inverted arch and the side wall and has a small effect on the arch,the bending moment of the secondary lining at the inverted arch and side wall decreases,the axial force of the secondary lining at the inverted arch increases,the axial force of the secondary lining at the foot of the wall decreases,the safety coeff icient of the secondary lining at the inverted arch and the side wall both increase with the rise-span ratio of inverted arch increasing.The safety coeff icient at the foot of wall is less than 2 when the rise-span ratio of the inverted arch is 1/11.87,which does not meet the requirements of the code.Therefore,the rise-span ratio of inverted arch should be increased for tunnel design in the swelling rock stratum.

关 键 词：铁路隧道 膨胀岩地层 数值分析 仰拱矢跨比 二次衬砌 力学特性 

分 类 号：U451.4[建筑科学—桥梁与隧道工程]