Groundwater Seepage Assesment at 4/6 km of of Tehran Metro Line 7 Tunnel whit SEEP/W Software and Comparison with Analytical Methods and Obsevations

Groundwater Seepage Assesment at 4/6 km of of Tehran Metro Line 7 Tunnel whit SEEP/W Software and Comparison with Analytical Methods and ObsevationsOne of the important problems in the construction metro tunnels under ground watertable is the problem of water enterance into the tunnel, which can completely affect the tunnel construction activity. There are several ways to solve these problems. In order to lower the groundwater level in a section of the Tehran Metro line 7 tunnel(4.6 Kilometers), From two galleries with length 14 meters Along the tunnel is used. Water drainage modeling and comparing its results with analytical results and observations are reviewed in this paper. In order to find out the performance of such software, in this paper, by considering the actual data of the tunnel line 7 of Tehran subway, 4.6 Kilometers, a model of the tunnel in the SEEP/W software, was simulated, To calculate the water input to the tunnel and drainage. The results show that the seepage rate calculated in the numerical method is 640 (cubic meters per day) and the analytical is 747.3 (cubic meters per day) which have a good agreement in calculating the rate of groundwater infiltration into the tunnel. The finite element method error is 11%, ,which indicates its ability to estimate the amount of water entering and exiting the tunnel thus, this software is reliable for modeling and achieving the desired goals. Also, effective factors such as changes in gallery distances from the tunnel and parameters such as permeability and water head were investigated, which had the greatest effect on the water entering the tunnel.