Study On Advanced Treatment Technology And Application Of Mining Subsidence Area With High Groundwater Levels

As the main basic energy,coal resources have promoted the rapid development of China's economy.There are abundant coal resources in high groundwater levels mining areas in eastern China,it is generally characterized by deep burial,multiple coal seams,high groundwater levels,and thick loose layer.The exploitation of coal resources leads to a long surface subsidence period,large subsidence coefficient and serious water accumulation on the surface of the mining area.In the subsidence area,the land function is seriously degraded,a large number of cultivated land is damaged,the surface buildings are submerged,and the ecological system is transformed.In order to improve the utilization rate of soil and water and the reclamation efficiency of mining subsidence area with high groundwater levels,this paper took the typical high groundwater levels mining area of Huaibei as the research object,the advanced treatment technology of mining subsidence area with high groundwater levels was developed.Based on the subsidence prediction model of probability integral method,the boundary model of "deepdigging and shallow-filling" and the surface elevation reconstruction model were constructed.The construction technology of the advanced treatment technology of mining subsidence area with high groundwater levels was designed.The engineering practice was carried out in Wugou Coal Mine and the reclamation area of Middle Lake in Huaibei,the effect of reclamation and the law of filling subsidence were analyzed.The research content and research results of the paper mainly includes following parts:(1)The advanced treatment technology of mining subsidence area with high groundwater levels was put forward.Firstly,the probability integral method is used to predict the surface subsidence before the working face mining,in the light of the characteristics of surface subsidence,the mathematical model of the surface "deep-digging and shallow-filling" boundary is determined,the surface elevation reconstruction models of digging area and filling area are constructed.Secondly,in order to increase the available land area in the subsidence area,the land surface is reconstructed and the soil in the area with large subsidence depth was reclaimed to smaller area of subsidence.Finally,after the mining of the working face is completed and the surface water is stabilized,governance in different directions and the reconstruction of ecological system was carried out.Through the implementation of advanced treatment technology,land reclamation efficiency can be increased effectively and land utilization rate can be improved(2)On the basis of the prediction model of subsidence by probability integral method,the boundary model of "deep-digging and shallow-filling" and the surface elevation reconstruction models are constructed.The subsidence characteristics of the strike main direction was be as the reference surface,combined with the balance of earth volume,the mathematical model of "deep-digging and shallow-filling" boundary is derived and the relevant parameters are determined,the surface elevation models of each region are determined according to the boundary model of "deep-digging and shallow-filling".The influence of main surface deformation parameters,such as subsidence coefficient,mining influence propagation angle and main influence angle tangent,on the boundary of "deep-digging and shallow-filling" is analyzed.This study combines the mining subsidence theory with the land reclamation work,and provides theoretical guidance for the advanced treatment technology of "deep-digging and shallow-filling" in the subsidence area with high groundwater levels.(3)The advanced treatment technology of mining subsidence area with high groundwater levels was be as the core,construction technology is designed.Based on the process principle and the characteristics of the work method,the process flow was designed,the plan of excavation and fill construction design and survey,onshore and underwater borrowing construction was made.In combination with the site environment,mud discharge and drainage pipelines were arranged,leveling and greening transformation was implemented on the surface after treatment.(4)Based on the research background of Huaibei Coal Mine,Anhui Province,the advanced treatment technology of mining subsidence area with high groundwater levels was practiced,the effect of advanced reclamation of "deep-digging and shallow-filling" and the law of surface subsidence were studied.Practice shows that,through "deep-digging and shallow-filling",a total of 54.69% of the land in the subsidence area was transformed into arable flat land,and 31.55% of the land was used as slope land for planting trees,irrigation and grass,13.76% of the ponding area was used as breeding area,and all the land in the subsidence area was used,which greatly improved the land use efficiency.The settlement period of filling area is divided into two stages: rapid settlement period and stable period,the average settlement rate is 3.9 mm/d and 0.65 mm/d,respectively.The period of rapid settlement is about 30 d,after which it gradually tends to be stable,which can meet the needs of land reclamation in the subsidence area,it provides theoretical basis and technical reference for land reclamation and ecological restoration in mining subsidence area with high groundwater levels.