破碎碳质灰岩地质情况下半明半暗偏压隧道进洞施工优化技术研究

Research on Optimization Technology for Construction of Half Bright and Half Dark Bias Pressure Tunnel under Broken Carbonaceous Limestone Geological Conditions

半明半暗偏压进洞施工方法利用隧道洞口围岩自身稳定性,首先施作截水天沟,并将水流引至自然水沟;在施工护拱前,对护拱及偏压挡墙基础进行处理,优先施工偏压挡墙,挡墙施工完成后可施工护拱。施工时分侧拉槽施工隧道护拱基础并对边仰坡进行挂网喷锚临时防护;待基础施工完成后进行护拱施工,强度达到时进行超前大管棚的施工,完成后对该段拱顶土体回填反压,洞口稳定后再进洞施工。该方法可为相似地形的进洞施工提供有益借鉴。

The construction method of half light and half dark bias pressure entering the tunnel utilizes the stability of the surrounding rock at the tunnel entrance.Firstly,a water intercepting gutter is constructed,and the water flow is directed to the natural gutter.Before the construction of the arch protection,the foundation of the arch protection and the eccentric pressure retaining wall should be treated,and priority should be given to the construction of the eccentric pressure retaining wall.After the construction of the retaining wall is completed,the arch protection can be constructed.During construction,the tunnel arch protection foundation will be constructed by side pulling grooves,and temporary protection will be provided for the side and front slopes with mesh spraying and anchoring.After the foundation construction is completed,the arch protection construction will be carried out.When the strength reaches the standard,the construction of the advance large pipe shed will be carried out.After completion,the soil at the arch top of the section will be backfilled and backpressed,and the tunnel will be stabilized before entering the tunnel for construction.This method can provide useful reference for tunnel construction in similar terrains.