隧道穿越富水泥岩断层破碎带超前帷幕注浆技术

Advanced Curtain Grouting Technology for Tunnel Crossing Fault Fracture Zone with Water-rich Mudstone

郑万高铁巴东隧道穿越的三叠系中统巴东组泥岩,具有一定膨胀性,遇水软化,自稳性差,在三峡库区被称为"易滑地层",并且隧道洞身穿过50 m长断层破碎带,采取有效的地层加固措施极为必要。在对泥岩基本地质特性分析的基础上,针对性地提出了超前帷幕注浆方案,并结合洞身超前管棚提高帷幕胶结体的承载能力,最后通过钻孔成像、现场监测等方法对帷幕注浆效果进行评价。实践表明,帷幕注浆后,掌子面围岩加固止水效果良好,有效保证了富水泥岩断层破碎带的稳定性,确保隧道施工安全。

Badong Tunnel of Zhengzhou-Chongqing High-speed Railway passes through mudstone of middle tiassic Badong formation,with a certain expansibility,softening in water and poor slf-stability,which is often rlered as"sippery stratum"in the Three Gorges Reservoir Area,futhermore,the tunnel body pases through 50 melers long fault fractured zone,so it is very necessary to take ffctive reinforement measures.Based on the analysis of the geological characteristics of the mudstone,a specifie advanced curtain grouting scheme was put forward.In combination with the advanced pipe shed of the tunnel body that improved the bearing capacity of the curtain cementing body,the efeet ol curtain gouting was evaluated by borehole imaging and field monitoring,Practice shows that the water-stop and reinforcement ffeet of surrounding rock is well after curtain grouing,which ffectively guarantees the stability of fault fracture zone of water-rich mudstone and the safety of tunnel construction.