Impact Analysis of Metro Tunnel Construction on Groundwater Flow in Nanchang, China

Abstract

Five metro lines are planned to be constructed in Nanchang. Metro tunnel will go through or cut off Nanchang Quaternary aquifer, which is bound to have a significant impact on the groundwater flow. This paper aims to construct a hydrogeological conceptual model after analyzing the hydrogeological conditions of the target area. Accordingly, the numerical simulations of the groundwater flow of the target area were conducted by applying the GMS software. After the model is calibrated, the five metro lines are considered as a whole to predict the influence of metro tunnel construction on the groundwater flow in Nanchang. The study shows that due to the influence of the subway tunnel barrier, the groundwater level is lifted in upstream face of the tunnel, and the lifting effect will accumulate with the passing of time. However, the groundwater level drops in the downstream face of the tunnel, and the dropping effect will accumulate with the passing of time, too. In the area between groundwater drop funnel in the east and groundwater mound ​​in the southwest, the lifting and dropping fluctuate with the change between upstream face and downstream face. And the other rising and declining are up to the alternation of principle influence factors. The sensitivity analysis of precipitation shows that that water level changes are very sensitive to precipitation.