炭质页岩隧道循环式高压注浆预加固技术

Cyclic High Pressure Grouting Pre-Reinforcement Technology for Carbonaceous Shale Tunnel

针对层状炭质页岩地层中隧道围岩破碎,遇水易软化等特点,依托郑万高铁罗家山隧道,通过方案比选,确定了采用循环式高压注浆预加固技术;同时对注浆参数进行了多工况的现场试验,明确了采用"稀浆(水灰比3∶1)劈裂,浓浆(水灰比0.5∶1)灌注"的施工方法,确定了相应的岩体注浆参数;注浆施工时应采用高压风代替传统清水清孔,浆液配置时通过添加减水剂来减少水的用量。实践表明,采用循环式注浆预加固处理后,浆液沿层理扩散且能形成较高强度的结石,有效控制了围岩变形,为隧道的安全施工提供了保障。

In view of the characteristics of the tunnel surrounding rock in the layered carbonaceous shale formation being broken and easy to soften in contact with water,relying on the Luojiashan Tunnel of the Zhengwan High-speed Railway,through the comparison and selection of schemes,the use of circulating high-pressure grouting pre-reinforcement technology is determined.At the same time,the grouting parameters are tested on various working conditions,and the construction method of“thin grout(water-cement ratio 3∶1)splitting and thick grout(water-cement ratio 0.5∶1)pouring”is clearly established.Then the grouting parameters of the rock mass are determined.High-pressure wind is used to replace the traditional clear water to clear the holes during construction,and water reducing agent is added to reduce the amount of water when the slurry is configured.Practice has shown that after pre-reinforcement by circular grouting,the grout spreads along the bedding and can form higher-strength stones,effectively controlling the deformation of the surrounding rock and providing a guarantee for the safe construction of the tunnel.