166 New Calculation Method of Tunnel Water Inflow Quantity and It's Application in Qiyueshan Tunnel

The water intrusion is a common problem in tunnels, however, the factors affecting water-gushing amount are so complex that the current prediction methods have their limitations because of the difference of geology environment although there many mathematic methods. On the basis of Karst hydrogeological condition of Qiyueshan tunnel, water inflow quantity is predicted by seeping coefficient of rainfall method, engineering comparison and finite element method. The FE method has an advantage in calculating water inflow in Karst tunnel for each section. The calculation has two steps which are respectively constructing orifice free-flow equation and FE numerical simulation. And the results reflect the change of water inflow quantity of positions in different distance apart from tunnel mouth and its relation with flow and velocity. Compared with the results from other methods, the FE calculating method is of great practical value which can reflect the whole process of tunnel water discharge more deeply and completely when we use this method to calculate water inflow quantity with other methods at the same time.