高压富水岩溶隧道注浆机理及作用效果分析

Analysis of Grouting Mechanism and Its Effect for Karst Tunneling in High Water Pressure and Water-enriched Region

高压富水岩溶隧道施工中存在很高的安全风险,常面临涌突水防治、围岩稳定性控制和衬砌高水压处理等技术难题,实施可靠的超前地质预报和有效的注浆是解决上述难题的关键。基于穿越高压富水岩溶区的圆梁山隧道工程,采用综合地质预报技术准确探明了溶洞的形态及其充填物性质;通过理论分析揭示了岩溶隧道的注浆机理;利用数值模拟确定了合理的注浆参数;通过复合注浆形成了可靠的注浆加固圈。监测结果表明:注浆圈起到了加固围岩、稳定工作面、封堵地下水和降低衬砌外水压力的综合作用,隧道施工中工作面稳定,围岩变形不大,堵水效果显著,达到了5m3.m-1.d-1的隧道限量排水控制标准,并实现了小排水量条件下有效降低衬砌外水压力的目的。研究成果对高压富水岩溶隧道建设具有借鉴意义。

Karst tunnels with high water pressure and rich water have very high risk during construction.They are commonly faced with the technical problems such as water burst prevention,surrounding rocks stability control and treatment of high water pressure on lining.Reliable geology forecasting and effective grouting is the key to solve the problems.Based on the project case of Yuanliangshan tunnel located at high water pressure and water rich regions,the methods of exactly forecasting the site,shape and filing of karst caves were introduced; the mechanisms of grouting were systemically analyzed; and the appropriate grouting parameters were decided according to numerical analyasis. By muhiple grouting the effective grouting circle were formed. The monitoring data show that the grouting circle attains the effects of reinforcing surrounding rocks, stablizing the working face, blocking ground water and reducing water pressure on tunnel lining. The surrounding rocks keep stable and their deformation is very small during tunneling. The drainage control standard of 5m^3 . m^-1 . d^-1 is also achieved, and the water pressure on tunnel lining is reduced remarkably with low discharge. The research result can provide references for similar karst tunneling in high water pressure and water - enriched region.