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

Abstract:

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.