Investigation of steady water inflow into a subsea grouted tunnel

This paper investigates analytical solutions for steady water inflow into a subsea grouted tunnel. The relevant parameters include the pore pressure distribution in the aquifer, external water pressure on the grouted zone and water inflow. Analytical solutions are obtained by the complex variable method (CVM), mirror image method (MIM) and axisymmetric modeling method (AMM). A series of numerical simulations are performed to validate the analytical solutions. The calculation accuracy and application conditions of each method are stated by comparisons of the pore pressure distribution and water inflow. Finally, the influencing factors, such as the boundary conditions, permeability of grouted zone and water depth, are discussed. It is suggested that the width of the lateral boundary should be at least nine times the tunnel diameter when conducting a numerical simulation for the steady seepage field. The relative permeability (i.e., kr/kg) has influences on comparisons between the analytical solutions and numerical solution, but the results remain in an acceptable range. It is also found that both the external water pressure on the grouted zone and water inflow increase linearly with the rising of the water table.