Study on the effect of micro-disturbance dual liquid grouting repair in subway tunnels

Urban operating subway tunnels are susceptible to structural deformation problems due to factors such as geological conditions, construction disturbances, and train loads. Traditional reinforcement methods are difficult to meet the precise repair needs under operating conditions. This study focuses on the application and effectiveness of micro disturbance grouting technology in the tunnel section between Xianghu Station and Binkang Road Station of Hangzhou Metro Line 1. Install grouting holes in the tunnel segments and inject cement water glass dual liquid slurry into the underlying soil layer in sections at a pressure of 0.2~0.3 MPa. The slurry solidifies to form a solid, improving the formation with low disturbance and enhancing the bearing capacity. Monitoring of the X568~X597 ring settlement over control section shows that after grouting, the maximum settlement of the roadbed decreased by 4~5 mm, and the settlement rate decreased from −0.173 mm/d to below −0.04 mm/d; The average convergence deformation decreased by 19%, and the rate decreased from 0.059~0.233 mm/d to 0.02~0.03 mm/d; The horizontal displacement offset is suppressed, and all indicators meet the design requirements. Research has confirmed that this technology can accurately control the shape and improve the performance of soft soil, providing an efficient path for repairing operational tunnels.