超前预注浆技术在高压富水岩溶隧道中的优化应用

Optimal Application of Advance Pre-grouting Technology to High-pressure Water-rich Karst Tunnel

为避免在高压富水岩溶隧道施工过程中发生突水突泥,改善施工环境,加快施工进度,依托我国沿海地区某岩溶隧道,分析原全断面超前注浆加固方案在施工中存在的问题,从开孔设计、注浆材料、注浆参数等方面对原方案进行优化,提出并应用基于上半断面开孔的外堵内固精细化超前注浆技术,结果表明:1)上半断面开孔方式能避免反复拆装钻孔工作台架,可节约工期4天/循环;2)基于"一孔多用"和"边注浆边检查"两大原则,后序检查孔可及时检查前序注浆效果,在满足设计要求的前提下,可实现快速开挖;3)采用硫铝酸盐单液浆,既能确保堵水效果,又能实现快速开挖。通过现场应用,每个注浆循环加快工期61.11%,每延米节约注浆材料47.79%。

In order to avoid the risk of water inrush and mud gushing during high-pressure water-rich karst tunnel construction, improve the working condition and shorten the construction schedule, the problems of orginal full-face advance grouting scheme in construction of a high-pressure water-rich karst tunnel in China are analyzed. And then the original construction scheme is optimized in terms of opening design, grouting materials and grouting parameters. Finally, a fine advance grouting technology, sealing outside and reinforcing inside applied to upper cross-section, is proposed. The application results show that ： （ 1 ） Drilling holes in upper cross-section of tunnel face can avoid repeated work of drilling platform disassembling and assembling, which can reduce construction period by 4 days per cycle. （2） According to the principle of one hole for muhipurpose and grouting while examining, the grouting effect of previous holes can be examined, which can achieve rapid excavation. （3） By using sulphoaluminate single slurry, the water stop effect and rapid excavation can be guaranteed. The site application shows that the grouting time per cycle is increased by 61.11% and the grouting material per cycle is reduced by 47.79%.