Abstract:

To investigate the seepage field of parallel fourtube mountain tunnels considering lining, the analytical solution of the seepage field of parallel fourtube mountain tunnels is derived using a comprehensive image method and the superposition principle. Then, the solution is degenerated into the seepage field analytical solutions of single, double, and tripletube tunnels and compared with existing results. Moreover,  the analytical solutions are validated using numerical simulation results, and the influence laws of tunnel spacing, tunnel relative dimension, and primary support parameters on water inflow and primary support outer pressure are analyzed. The results reveal the following: (1) The influence of tunnel spacing between adjacent tunnels is more significant on the seepage field of parallel fourtube tunnels, but the influence can be ignored if the tunnel spacing is >20 times the radius of the tubes. (2) If the diameter of one tube of the tunnel increases, its water inflow increases accordingly, decreasing the water inflow in the other three tubes. (3) With a decrease in the permeability coefficient and an increase in the thickness of the primary support, the water inflow in a tube gradually decreases, the water pressure after the primary supporting gradually increases, and the interactions between tubes gradually weaken.

Key words: parallel fourtube tunnel, seepage field analysis, image method, seepage flow, water pressure