XX公路XX标段XX隧道位于XX市XX县城南郊XX，隧道穿越XX山，进口里程K2+423，出口里程K3+195，全长772m，路线设计纵坡-3%、-0.094%。进口30.632m及出口段192.75m分别位于半径为120m及200m的曲线上，其余地段位于直线上。
进口K2+433～+488段55m，为Ⅱ类围岩，隧道位于坡积碎石土层上，含水量大，埋深浅，工程力学性质差，围岩开挖后易坍塌，成洞困难。于隧道拱部120°范围采用超前大管棚注浆支护辅助施工（大管棚共布置两环），边墙及仰拱采用超前小导管注浆支护辅助施工。且设2榀/m拱、墙、仰拱格栅钢架加强支护。
目 录
1.前言··············2
2.工程概况············2
2.1概述·············2
2.2大管棚变更情况·········3
2.3大管棚超前支护方法·······4
3.施工工艺············7
3.1测量放样···········7
3.2钻孔··············9
3.3配管············11
3.4送管·············12
3.5下钢筋笼···········13
3.6管口封闭··········13
3.7注浆············13
3.8沉降观测···········18
3.9事故预防和处理········18
3.10机具设备和劳力······19
4.安全措施···········20
5.结论·············21
6.相关知识点··········21
7.主要参考书目·········24