Yin Liming

The effects of mining subsidence and drainage improvements on a waterlogged area

Subsidence caused by mining can lead to serious waterlogging problems. In this study, numerical simulation was used to predict both subsidence and waterlogging in a coal-mining area. Changes in the phreatic surface and the area of waterlogging caused by mining subsidence were estimated for various mining scenarios using field measurements and simulation analysis. The results of the numerical simulation for the area of waterlogging caused by existing mining subsidence agreed well with the measured results. The simulation results showed that further mining will cause additional subsidence and increase the extent of the waterlogged areas. The numerical simulation method was used to analyze the effects of improvements to the drainage system for different mining scenarios. The improvements included additional drainage channels and raising the height of river embankments to prevent flooding. The results showed that the western drainage improvements have decreased the water table by about 1.0–1.3xa0m after mining of the No.2 coal seam, while the eastern drainage improvements would decrease the water table by about 2.0xa0m after mining of the No.4 coal seam. Thus, the area of waterlogging could be effectively managed.