<p>Tunnels in mountainous areas with abundant groundwater would be subject to high water pressure if the drainage system is inadequate. Considering a railway tunnel under construction in China, a coordinated drainage scheme is proposed by utilizing both the tunnel with an embedded pipe network and a parallel pilot drift with inclined drainage boreholes. A numerical model of coupled flow in the surrounding rocks and the drainage pipes is developed to study the effects of various drainage schemes on the mechanical responses and the factors of safety of the lining. Comparative analyses have found that if the scheme is only tunnel drainage, the water pressure on the lining will increase dramatically with the permeability of the strata once the rock permeability is larger than a critical value (the critical value is related to the drainage parameters of the embedded pipe networks). Therefore, the safety of different lining sections is also significantly reduced. However, with the coordinated drainage scheme, the water pressure on the lining is released to a greater extent. The maximum water level the lining can withstand significantly increases. Even in the case of highly permeable formation, water pressure is not the main factor restricting the safety of the lining.</p>