地铁暗挖隧道断层破碎带突水涌砂原因分析及处治技术

Causes Analysis and Countermeasures for Water Inrush and Sand Gushing in Fault and Fracture Zone during Mined Metro Tunnel Excavation

青岛黄岛区某地铁区间隧道穿越断层破碎带时发生突水涌砂地质灾害,为保证隧道施工安全及后续顺利开挖,对富水断层破碎带突水涌砂原因及力学形成过程进行分析。富水断层破碎带稳定性差,未进行有效加固,在开挖卸荷和爆破扰动双重作用下,岩体防突水层厚度超过临界状态,进而导致掌子面发生突水涌砂。考虑到地铁暗挖隧道施工空间狭小、材料运输不便等特点,采用以地表模袋注浆为主、洞内堵水注浆为辅的综合处治措施。结果表明:注浆加固后的掌子面湿润无流动水,浆脉清晰可见,渗漏水量小于1.5 L/(min·m),渗流通道得到有效封堵,保证隧道顺利通过突水涌砂段。

The causes and mechanical processes of water inrush and sand gushing of water-rich fault and fracture zone are analyzed so as to guarantee the safe construction of a mined metro tunnel in Huangdao District of Qingdao City.Under the action of excavation unloading and blasting disturbance,the thickness of waterproof layer of surrounding rock in water-rich fault and fracture zone with poor stability and without effective reinforcement exceeds limit,which leads to water inrush and sand gushing disaster.The comprehensive countermeasures of membrane bag grouting on ground surface and water stop grouting in tunnel are adopted considering disadvantages of mined metro tunnel construction,i.e.limited space and inconvenient material transport.The grouting effect shows that the working face after grouting is moist and with no flow water,the water leakage has been control within 1.5 L/（min·m）;the seepage channels have been successfully sealed;and the safe and successful construction in water inrush and sand gushing sections of metro tunnel has been guaranteed.