Study on multi-arch tunnel leakage disease with influence of rainfall and groundwater change

It is known that the tunnel leakage is significantly affected by precipitation, for example the seasonal rainfall and the groundwater level change, which reduce the effective stress and the shear strength of the surrounding rocks, resulting in surrounding rock fracture and the connection of crack path between surrounding rock and lining structure. This paper reveals the relationships between the tunnel leakage with the lining crack width, the surface seepage, and the construction joints. Then the calculation equations of leakage water are deduced. According to the deduced equations, the influence of rainfall and groundwater level on leakage of the multi-arch tunnel is analysed. It is concluded that the leakage water increases with the rise of ground water level, decreases with the increase of the thickness of the lining; and the spot leakage and the surface leakage both increase as the increasing of the crack width and the seepage radius. On the basis of the conclusions, the preventions and treatment measures of leakage caused by rainfall and groundwater level change are put forward to ensure the long-term safe operation of the multi-arch tunnel.