Study On The Experiment And Formation Mechanism Of Water Movement In Unsaturated Zone Of Huaibei Coal Mining Subsidence Area

Coal is the main energy in China,caused by the surface subsidence due to coal mining and led to inevitably unsaturated soil damage to the original structure,the influence of groundwater circulation,thereby affecting the restoration of subsidence area.This paper takes Huaibei Shitai coal surface mining subsidence in the process of water migration in unsaturated zone as the object,through field experiments,water potential and water change characteristics in the process of settlement observation system,using statistical methods of mining under(including precipitation and evaporation)in unsaturated zone,the vertical water movement on the law water distribution,water characteristic curve and the determination of hydrogeological parameters.The results show that the mining ground subsidence induced by the disturbance of the unsaturated soil within the primary structure,the development of micro cracks,caused by the soil permeability coefficient,variation of unsaturated hydraulic conductivity and other parameters,reduce the water holding capacity of unsaturated soil.At the same time,HYDRUS-2D software is used to simulate and compare the water migration in unsaturated zone.The simulation results show that the changes in rainfall,evaporation and groundwater conditions,subsidence of unsaturated soil of different depth position of the volumetric water content compared to the non subsidence area will produce bigger fluctuation.