| The root cause of the water inrush in the roof is the change of the mining stress in the coal seam mining process,and the groundwater migration law is changed under the coupling of the seepage and stress.When the coal seam roof is filled with confined aquifer,the roadway and coal seam mining will cause The original stress balance state of the overburden is destroyed,and the fall zone,the fracture zone and the curved subsidence zone are formed from the bottom to the top.The coupling of the stress field and the seepage field causes the water to have large water volume,sudden strongness and complicated path.Features.Therefore,the system studies the water inrush path and evolution law of aquifers in different spatial locations during the coal seam propulsion process under the coupling of stress and seepage,and correctly understands the water inrush mechanism of the working face,which is important for coal mine safety production,disaster prevention and early warning,and water resources protection and utilization.When the confined aquifer is above the fracture zone,the confined water acts mainly on the underburden by degrading the dissolution and splitting;when the confined aquifer is between the fall zone and the fracture zone,the confined water mainly passes through the squeeze and Infiltration and other methods act on the underlying strata and the working face;when the confined aquifer is within the fallen zone,the confined water enters mainly in the lateral replenishment mode and acts on the working face.Aiming at the migration problem of groundwater flow field caused by different spatial positions of confined aquifer and coal seam,this paper studies the coupled mechanical evolution model of confined aquifer above coal seam and the study of transverse permeability of aquifer rock.Under the coupling of stress and seepage The establishment of numerical models,the analysis of the gushing water path and mechanism of the working face,and the engineering application of the water inflow prediction method,using theoretical analysis,physical testing,field experiments,numerical simulation and on-site monitoring data analysis,coupling stress and seepage Under the action of the working face,the water inflow path and mechanism development system research,the following research results:1.Carry out theoretical analysis of different spatial positions of confined aquifer and coal seam.According to the situation that the confined aquifer is above the fracture zone,establish a stress-seepage coupling model of the composite bearing layer and hydrostatic pressure in the non-damage state,and quantify the degradation corrosion.The critical water pressure value of the water-permeable layer under the action of the water layer;the stress-seepage coupling model of the composite bearing layer and the hydrostatic pressure under the condition of bending deformation is established for the confined aquifer between the fracture zone and the fall zone,and a set of stress is established.The criterion of critical layer damage criterion under the coupling of seepage and flow;for the case that the confined aquifer is located within the fall zone,the coupled mechanical model of stress and seepage of the M-type structure is established,and the evolution law of the coupled structure of stress and seepage under continuous mining of working face is studied.The "V"-"M" rock formation transformation model is established,and the maximum support stress analytical formula of the coal body in front of the working face with the extraction distance as the variable under continuous mining conditions is obtained.2.Through the self-designed transverse permeability measurement system,referring to the stress variation characteristics in the actual mining process as the loading path,the lateral permeability evolution law of the aquifer rock above the working face under the mining stress is studied,and the quantitative infiltration is studied.The relationship between the permeability and the stress of the vertical stress,the experimental results show that,according to the specific loading path designed by the actual mining process,the permeability of the sandstone changes with the stress state,which shows a process of sharp decline and then stable and small fluctuation plasticity.Based on the permeability-stress relationship between the transverse permeability and the vertical stress,the stress-transverse permeability constitutive relation under stress-seepage coupling is proposed.The numerical simulation software COMSOL is used to study the stress-seepage coupling solid stress field and The variation law of fluid stress field has obtained the characteristics of the aquifer's advanced seepage reduction phenomenon,that is,the permeability coefficient of the aquifer rock decreases during the process of increasing the pre-support pressure and the confining pressure,revealing different mining distances and different coal seams.The variation of the aquifer infiltration and the infiltration reduction under the thickness,water pressure and roof management mode;4.Select the large well method and the narrow horizontal tunnel method to predict the change of water volume on the working face and compare it with the actual water inflow data of the working face;compare and analyze the actual mining pressure law and the water inflow from the working face;In this paper,the law of groundwater migration under the coupling of stress and seepage is discussed.Taking the Mindong mining area as an example,the water inrush stage of the working face is divided into the working face opening stage,the ? containing water layer starting to fall stage,and the ? containing aquifer.In the complete degeneration stage,the stage of formation of the aquifer containing ? and the formation stage of the composite bearing layer structure,the water inflow,velocity,water source,characteristics and mechanism of each stage are studied in detail,and the coal mine safety production and disaster prevention are carried out.And early warning and the protection and utilization of water resources are of great significance. |
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