LAUSR

Penetration of the landfill leachate during a tunnel excavation process has a certain impact on the properties of surrounding rocks, including their permeability. The present study was envisaged to analyze such changes by performing a comparative test on the rock specimens with or without being soaked in the landfill leachate. Furthermore, the groundwater flow and solute transport model were established. Tunnel drainage was conceptualized as a pumping well in the confined formation and the weighting factor for hydraulic conductivity coefficient was taken into consideration for specific regions in the model. Subsequently, the water level and the pollutant concentration distribution in these regions were analyzed. The results showed that the simulated groundwater levels on the south and north sides of the tunnel were higher than the original level. Fluctuation in the groundwater level caused by the tunnel drainage was significantly greater due to pumping well PW-1. Because of the soaking of the surrounding rocks in the landfill leachate, the hydraulic conductivity coefficients of these regions increased, which aggravated the downward penetration of the pollutants in the regions between the two tunnels.