浅埋隧道施工中大管棚超前支护技术的应用

Application of Large Pipe Shed Advance Support Technology in Shallow Tunnel Construction

在概述H隧道工程浅埋段地质条件特殊性的基础上进行了超前支护技术的比选和施工方案的设计,并对包括导向墙施工、钻孔、管棚加工、钢筋笼制作安装、注浆等环节在内的大管棚超前支护施工过程进行分析探讨。分析结果表明,大管棚超前支护技术能通过注浆将松散土体及加固支护材料有效固结,使刚性管棚和注浆体形成整体性受力结构,并能在隧道开挖轮廓线以外形成支撑体,防止围岩恶化,有效避免浅埋隧道段掘进过程中发生围岩变形、坍塌冒顶事故。

On the basis of summarizing the particularity of geological conditions in the shallow buried section of H tunnel project,the comparison and selection of advanced support technology and the design of construction scheme are carried out,and the construction process of large pipe shed advanced support including guide wall construction,drilling,pipe shed processing,reinforcement cage fabrication and installation,grouting and other links is analyzed and discussed.The analysis results show that the large pipe shed advance support technology can effectively consolidate the loose soil and reinforcement support materials through grouting,form an integral stress structure between the rigid pipe shed and the grouting body,form a support outside the tunnel excavation contour,prevent the deterioration of surrounding rock,and effectively avoid the deformation,collapse and roof fall of surrounding rock during the excavation of shallow tunnel section.