Numerical Simulation for Impacts of Mountainous Tunnel Drainage on Groundwater Environment

Mountainous tunnel drainage can cause various negative impacts on the groundwater environment and human life; as a result, it is necessary that the drainage is quantitatively estimated and minimized during the construction period. In this study, a numerical model was conducted to predict the influences of mountainous tunnel drainage on the groundwater environment in northern China. The results show that the drainage would change the groundwater flow field and form drawdown funnels; however, it would not cause regional groundwater drawdown. Besides, the discharge amount of springs was also affected by the tunnel drainage, and the maximum reducing amount was up to 25%. The storage resources of the aquifers were decreased under the effect of tunnel drainage. All negative influences could be gradually eliminated after the strong drainage. This research can provide effective methods to measure and decrease the impacts of tunnel drainage.