Tunnel surrounding rock seepage boundary conditions can be roughly divided into four types based on water level

drainage design and construction approach

and the seepage boundary conditions to adapt to different construction conditions are discussed in detail. An analytical formula to calculate pore water pressure in tunnel surrounding rock and tunnel water inflow under four kinds of boundary conditions is obtained by adopting the method of conformal mapping of complex function. Comparison between analytical solution and numerical solution confirms the correctness of the analytical solution. Based on the relationship between tunnel water inflow with buried depth diameter ratio ( )

as well as the relationship between surrounding rock pore water pressure and under different boundary conditions

the influence of boundary conditions on shallow-buried tunnels and deep-buried tunnels is analyzed. Selection of boundary conditions for shallow-buried tunnel seepage calculation is also discussed. The conclusions for tunnel seepage calculation and drainage design reported in this article provide theoretical guidance for engineering practice.