黄土地区浅埋大断面铁路隧道不同超前支护影响分析  

Analysis of the Influence of Different Advanced Support of Shallow Railway Tunnel with Large-section in Loess Area

作　　者：张忠[1] Zhang Zhong(China Railway 18th Bureau(Group)Co.,Ltd.,Tianjin 300350,China)

机构地区：[1]中铁十八局集团有限公司,天津300350

出　　处：《市政技术》2023年第7期176-181,共6页Journal of Municipal Technology

摘　　要：为了研究浅埋隧道中超前支护结构的承载性能,通过现场试验分析了隧道变形和支护结构力学特性演化规律,并建立了三维数值模型,从管棚安装角度、直径和横向间距等方面分析了隧道变形和支护结构力学特性。研究结果表明:隧道围岩压力的变化主要是由上台阶处的环形土开挖和下台阶开挖引起的;管棚安装角度越大,隧道拱顶沉降值就越大,安装角度的增加导致初期支护结构最大轴力减小;使用直径113.6 mm的管棚比使用直径60.3 mm的管棚更能有效地控制开挖引起的地表沉降,管棚直径越大,初期支护结构的最大轴力就越大;随着管棚横向间距的增加,隧道拱顶沉降值增加,且导致初期支护结构最大轴力减小。In order to study the load-bearing performance of the advanced support structure in shallow buried tunnels,the evolution laws of tunnel deformation and mechanical characteristics were analyzed through on-site experiments.A 3D numerical model was established to analyze the tunnel deformation and mechanical characteristics from the aspects of installation angle,diameter and lateral spacing of the pipe shed.The research results indicate that the changes of tunnel surrounding rock pressure are mainly caused by the excavation of the annular soil at the upper step and the excavation of the lower step;The larger the installation angle of the pipe shed is,the greater the settlement value of the tunnel arch is.The increase of installation angle causes decrease of the maximum axial force of the initial support structure;Compared with a pipe shed with a diameter of 60.3 mm,the use of a pipe shed with a diameter of 113.6 mm is more effective in controlling surface settlement caused by excavation.The larger the diameter of the pipe shed is,the greater the maximum axial force of the initial support structure is;With increase of the lateral spacing between the pipe shed is,the settlement value of the tunnel arch increases and causes decrease of the maximum axial force of the initial support structure.

关 键 词：浅埋大断面隧道 超前支护 参数优化 结构变形 数值模拟 

分 类 号：U455.4[建筑科学—桥梁与隧道工程]