高压富水硬岩地层双护盾TBM前置式超前注浆堵水技术研究

Research on Front⁃mounted Adcanced Grouting Water⁃stop Technology of Double Shield TBM Crossing High⁃pressure Water⁃rich Hard Rock Tunnel

晋中引黄输水隧洞双护盾TBM施工穿越高压富水裂隙,掌子面高压大流量突涌水严重,采用常规后置式超前注浆技术对掌子面突涌水进行超前处置效果不佳,主要原因是受外插角影响,采用常规后置式超前注浆存在注浆目标区域受限、钻探效率低、超前注浆控制难度大等问题,难以形成有效的止水帷幕结构。对隧洞水文地质条件、突涌水情况及超前注浆技术进行系统研究分析,提出双护盾TBM前置式超前注浆堵水工艺,通过优化注浆设备,在掌子面处实施超前注浆堵水。开展现场注浆试验,对坚硬岩面钻孔施工、注浆材料、注浆参数控制及注浆段长优化等技术进行研究,并根据现场试验信息,不断优化注浆设备及工艺。通过对晋中引黄输水隧洞实施前置式超前注浆堵水技术,洞内平均出水量降至3 702m~3/d,降幅达75.9%,同时在一定程度上提高了TBM施工效率。实践证明该技术方法有效。

The double-shield tunnel boring machine(TBM)construction of the Jinzhong Yellow River Water Diversion Tunnel crosses high-pressure and water-rich fractures,and the high-pressure and large-flow water inrush on the tunnel face is serious.The conventional rear-loaded pre-grouting technology was used to cope with the water inrush on the tunnel face but proved to be ineffective.The main reason is that due to the influence of the external angle,conventional rear-loaded pre-grouting has such problems as limited grouting target area,low drilling efficiency,difficulty in pre-grouting control,it is difficult to form an effective waterproof curtain structure.Through systematic study and analysis of the hydrogeological conditions,water inrush and pre-grouting technology of the tunnel,the double shield TBM front-loaded pre-grouting technology for water sealing is proposed.By optimizing the grouting equipment,the pre-grouting water sealing was implemented at the working face.The field grouting test was carried out to study the drilling construction,grouting materials,grouting parameter control and grouting section length optimization of hard rock surfaces.According to the field test information,the grouting equipment and technology were continuously optimized.Through the application of the pre-grouting water sealing technology in the Jinzhong Yellow River Diversion Tunnel,the average water yield in the tunnel is reduced to 3702m3/d,a decrease of 759%,and the TBM construction efficiency is improved to a certain extent.And engineering practice has proven that this technical method is effective.