湿陷性黄土地区超小净距隧道超前支护研究

为了研究湿陷性黄土地区超小净距隧道超前支护,现依托兰州南绕城高速公路柳泉3#隧道,采用GTS-NX有限元软件对超前管棚、水平旋喷支护及大管棚配合水平旋喷桩三种超前支护方案进行比选分析。计算结果表明,大管棚配合水平旋喷桩超前支护施工影响范围内地表竖向沉降量较小,初支无明显变形开裂、整体稳定性好,能够承受上方土体和交通荷载。该方案在现场工程应用中效果良好,依托工程隧道洞口超小净距段最小净距仅0.64 m,为国内已实施的湿陷性黄土地区最小净距隧道。

Study on Forepoling of Ultra-small Clear Distance Tunnel in Collapsible Loess Region

In order to study the forepoling of ultra-small clear distance tunnel in collapsible loess region,relying on Lanzhou South Ring Expressway Liuquan Tunnel 3#,GTS-NX finite element software is used to compare and analyze three forepoling schemes of leading pipeline shed,horizontal rotary shotcrete support and large shed with horizontal shotcrete pile.The calculation result shows that the vertical settlement of the ground is small within the influence scope of forepoling construction of large shed with horizontal shotcrete pile,and no obvious deformation and cracking are observed in the initial support,and the integrated stability is good,which can bear the upper soil and traffic load.This scheme has a good effect in the field engineering application.Based on the engineering tunnel entrance ultra-small clear distance section,the minimum clear distance is only 0.64 m,which is the minimum clear distance tunnel in the collapsible loess region implemented in China.