Research On Seepage Flow And Design Of Artificial Dam In Lingxin Coal Mine

In order to solve the problem of water resource waste caused by coal mining in Lingxin Coal Mine,reduce the loss of water resources in the mine,and realize water conservation and mining,use the underground water reservoir technology of the coal mine to store water in the mine goaf,use artificial dams and protect The coal pillars are connected to form a closed water storage space,and the changes in the seepage field in the mining area and the stability of the dam play a vital role in the safety of the groundwater reservoir.This article takes the Lingxin Coal Mine as the engineering background,and based on the mining area geological survey report and the actual situation on the site,the basic conditions of the mining area from mine development,mining area distribution,mine geological structure,distribution of aquifers and aquifers,and mine filling conditions are detailed Investigations were carried out,and the geological conditions of the mining area met the requirements for the construction of underground water reservoirs in coal mines.In order to determine the changes of the underground seepage field in the mining area with the progress of different working conditions,a two-dimensional seepage model along the No.4 exploration line was established.The model covers a total of 20 rock layers with different permeability coefficients,including the Quaternary overburden,1-17 # coal seams,water barriers between coal seams,lower rock masses,and 6 panels to be mined.By simulating 5 kinds of working conditions,it is determined that the groundwater reservoir in the north wing goaf of the first mining area of Lingxin Coal Mine has a low permeability and tightness,and will not affect the surrounding rock formations and mining areas.A waterproof dam is set to completely close the goaf of the north wing of a mining area,thereby achieving the purpose of sealing water storage.The safe coal pillar height of the dam is determined according to the "Code for the Design of Water Prevention and Control of Coal Mine" and other calculations.According to the calculation of the height of the roof water-conducting fissure zone and the thickness of the safety protection layer,there may be a hydraulic connection between the surface water and the underground reservoir.The pressure is 1.4 ? 2.7MPa,and the anti-sliding performance of the dam body is analyzed and explained by taking a straight wall dam body as an example.Considering the main loads of the dam body as dead weight,hydrostatic pressure,and friction,the relationship between the anti-sliding stability safety factor and the water head at three different coal seam thicknesses was obtained.A calculation model with the dam body and the coal pillar as the main body was established,and a cover was set.Rock and hydraulic conditions are used as calculation loads,and the characteristics of the forces under the action are studied to provide a reference for the design of the dam body.In order to improve the strength and airtightness of the surrounding rock,grouting of the surrounding rock is required.The grouting length should be no less than the width of the waterproof coal pillar.The grouting material is a mixed slurry of cement and water glass.The water-cement ratio is 0.75: 1.The volume ratio of mud liquid to water glass is 1: 0.5.In order to improve the anti-seepage and anti-corrosion properties of grouting,it is necessary to add a certain amount of ultrafine slag,preservative and retarder in the slurry.