富水粉细砂层盾构接收端头补充注浆加固技术研究及实践

Research and practice of grouting reinforcement technology for the receiving end of shield tunneling in water‑rich fine sand layers

华北平原某地铁区间风井盾构接收端头所处地层从上到下主要为粉质粘土、粘质粉土、粉细砂,且地下水位高,流动性强。接收端头经高压旋喷注浆加固后水平探孔发现仍然存在涌水涌砂风险,盾构机刀盘在破除洞门时极易发生洞门间隙处涌水涌砂。为保证盾构机顺利贯通出洞,采取地表袖阀管注浆的方式,采用GX改性硅灌浆料固结粉细砂,对区间风井接收端头富水粉细砂地层进行针对性的补强注浆加固。经过处理后盾构顺利出洞,未发生涌水涌砂。

The strata where the receiving end of air shaft shield is located in a subway section of the North China Plain is mainly silty clay,clayey silt and silty fine sand from top to bottom,with high underground water level and strong liquidity.After being reinforced by high‑pressure rotary jet grouting at the receiving end,it was found that there is still a risk of water and sand inrush using horizontal exploration holes.The water and sand surging is easy to happen in the gap between the tunnel doors when the cutterhead of the shield tunneling machine break through the tunnel door.To ensure the shield machine smoothly passing out of the tunnel,the method of surface sleeve valve pipe grouting is adopted,and the GX modified silicon grouting material is used to consolidate the fine sand.Targeted reinforcement grouting is carried out in the receiving end of the interval air shaft within the water‑rich fine sand formation.After treatment by such technology,the shield machine successfully excavated without any water or sand inrush.