Abstract
Karst geological regions, due to their unique geological structures and surface morphologies, frequently encounter hydrogeological issues such as water inrush, posing potential threats to the stability and safety of urban tunnels. This study investigates the impact of karst geological water inrush on urban tunnels through a combination of field monitoring and numerical simulation methods, and proposes a corresponding grouting-based water sealing scheme. The research findings indicate that: based on the deformation rate at different locations, the deformation throughout the entire monitoring period can be divided into three stages, namely the rapid change stage, the slow development stage, and the stabilization stage; the cavity water head of 10 m can be adopted as the critical cavity water head value; water inrush occurs in the tunnel when the water source pressure exceeds 0.5 MPa, with the water inrush volume continuously increasing as the water source pressure increases; water inrush occurs when the filler thickness is less than 10 m, with the water inrush volume continuously increasing as the filler thickness decreases. The implementation of the grouting-based water sealing scheme effectively controlled water leakage during tunnel excavation and support operations, ensured construction quality, reduced idle time and waste of construction personnel and mechanical equipment, and achieved cost savings.
Full Text
Research on the Impact of Karst Geological Sudden Water Inflow on Urban Tunnels and Grouting for Water Blocking Measures
WANG Yuedong
China Railway 16th Bureau Group Fourth Engineering Co., Ltd., Beijing 101400, China
Abstract
Karst geological regions, characterized by their unique geological structures and landforms, frequently encounter hydrogeological problems such as sudden water inflow, which pose potential threats to the stability and safety of urban tunnels. This study investigates the impact of karst geological sudden water inflow on urban tunnels using a combination of field monitoring and numerical simulation methods, and proposes corresponding grouting-based water control measures. The research results indicate that deformation during the monitoring period can be divided into three stages based on the rate of deformation change at different locations: a rapid change stage, a slow development stage, and a stabilization stage. A karst cavity water head of 10 m serves as the critical threshold value. Tunnel water inflow occurs when the water source pressure exceeds 0.5 MPa, with the inflow rate increasing as pressure rises. Additionally, water inflow occurs when the filling material thickness is less than 10 m, with the inflow rate increasing as thickness decreases. The implemented grouting-based water control measures effectively managed water seepage during tunnel excavation and support operations, ensuring construction quality while reducing idle time for personnel and equipment, thereby achieving cost savings.
Keywords: Karst geology, Sudden water inflow, Urban tunnel, Grouting for water blocking