浅埋偏压全风化花岗岩富水隧道综合注浆加固施工关键技术研究

Study on the Construction Technology of Comprehensive Grouting Reinforcement in Shallow Bias Fully Weathered Granite Enriched Water Tunnel

广东省东北部山区分布着大量的花岗岩地层,部分洞身处于浅埋偏压的不利状态下,全风化花岗岩富水隧道的稳定性差,开挖过程中掌子面难以自稳,注浆加固是保证隧道开挖安全的重要手段。本文以梅汕铁路大岭隧道溜塌段为研究对象,通过分析该段全风化花岗岩的成分及崩解特性,得到溜塌的原因,采用前进式(或后退式)注浆+多管注浆及后期地表注浆联合加固技术。隧道施作效果表明,该综合加固施工措施有效解决了全风化花岗岩段透水性强、遇水软化、掌子面难以自稳、初期支护变形大的难题。

A large number of granite strata are distributed in the northeast mountainous area of Guangdong Province.The tunnel portal sections are often in the unfavorable state of shallow buried bias pressure.The stability of fully weathered granite water rich tunnel is poor,and the tunnel face is difficult to be stable during excavation.Grouting re⁃inforcement is an important measure to ensure the safety of tunnel excavation.This paper took Daling tunnel of Mei⁃zhou-Shantou railway as the research object.Based on the analysis of the composition and disintegration characteris⁃tics of the completely weathered granite in this section,the causes of the collapse were obtained.This paper analyzed and introduced the combined reinforcement technology of forward(or backward)grouting,multi pipe grouting and lat⁃er surface grouting.The final tunnel construction results show that the comprehensive reinforcement measures effec⁃tively solve the problems of strong water permeability,softening in water,difficult to stabilize the face,and large de⁃formation in the initial support.