Analysis of Lining Water Pressure of High-Pressure Water-Rich Karst Tunnel Based on Fluid-Structure Interaction

To ensure the normal operation of the mountain tunnel with large burial depth and high water head, the water pressure of the tunnel lining should be accurately determined. The two-dimensional seepage around the tunnel meets Laplace equation, and the conformal variation theory is adopted to convert the free water surface of the underground water of the mountain tunnel and the periphery of the grouting circle into the circular ring with inner diameter of α and outer diameter of 1 in w plane. The universal solution of Laplace equation is obtained in the conformal variation circle area, and the analytical solution of the water pressure of the tunnel lining with steady seepage is deduced according to boundary condition and seepage continuity. Meanwhile, the analytical solution formula for the water pressure of the lining and the calculation software based on FLAC^2d finite difference method are adopted to calculate the analytical solution and the numerical solution of the water pressure of Ying-shan-yan tunnel lining of Chengdu-Guiyang Passenger Transport Line. The comparison between above two solutions shows that the analytical solution has higher practicability and reference value for calculating the water pressure of the high-pressure water-rich karst tunnel lining.