Study On Overburden Strata Movement Law Of Partial Backfill Mining With Gangue In Steeply Dipping Seam

During the mining of steeply dipping seam,there will be obvious zoning characteristics of the strata stress along the inclination direction of the coal seam,and the degree of load is uneven.Support slips,falls,and the squeezing and biting phenomenon intensifies,which seriously affects the stability of the support system.It is easy to cause safety accidents and seriously affect the safe and efficient production of the working face.The method of partial filling of artificial gangue can be used in the high-incline coal seam to deeply analyze the migration law of the overlying strata,which can provide a theoretical basis for solving the rock movement and the control of the pressure manifestation in the long-wall stope of the large-incline coal seam,and enrich the mining of the high-incline coal seam.The theory provides a scientific basis for filling and mining of high-incline coal seams,and the research has important theoretical and engineering significance..This thesis uses variable-angle two-dimensional physical similarity experiments,numerical calculations and theoretical analysis methods to study the overlying rock displacement changes,stress evolution characteristics,failure field range and overburden collapse morphology of the high-incline coal seam gangue partially filled stope.Further analysis of the law of overlying strata migration under different working conditions in high-incline coal seams,the research results show that:The migration characteristics of overlying strata after partial filling of artificial gangue in high-dip coal seams are affected by main factors such as the inclination angle of the coal seam,the length of the working face and the proportion of the working face with artificial gangue filling.The local gangue filling mining can effectively control the movement of the rock strata and reduce the collapse height of the overlying rock.Compared with no filling,1/3 of the length of the working face with gangue local filling can reduce the collapse height of the overburden by 42.58%,and the collapse range is only Appears in the unfilled area of the working face.When the proportion of artificially filled gangue is 1/3 of the inclined length of the working face,as the inclination of the coal seam increases,the stress value in the stress concentration area and the stress release area decreases,the roof and floor stress release is relatively sufficient,and the lower end of the unfilled area of the working face The damage field height of the overlying strata continues to increase,and the depth of the damage field at the top and bottom of the working face is constantly decreasing,and shear failure is the main cause.The damage field distribution of the overburden strike is the same;when the working face is inclined and the inclination angle is constant,compare filling There are two mining methods and non-filling mining methods.It can be seen that filling mining can effectively control the movement and deformation of the overlying rock and the scope of the damage field.The filling of the high-dip coal seam will change the original stress transmission path and movement direction of the overburden.When the filling increases from 1/3 to 1/2,the range of the overburden failure field decreases sharply,causing a sudden change;when the artificial gangue filling ratio and coal seam inclination angle are constant,the maximum concentration of stress will be the maximum value as the length of the working face increases.The coal pillar at the lower end of the working face is transferred to the upper end of the artificial gangue filling body of the working face.The filling body has a more obvious effect of weakening the concentrated stress of the coal pillar at the lower end of the working face.Analyze the mechanical characteristics and constraint conditions of the basic roof of the working face under the artificial gangue filling,and establish the deflection and rotation equations of the basic roof of the basic roof of the collapsed gangue filling area and the basic roof of the unfilled area,and finally determine the filling of the collapsed gangue The maximum stress point of the basic top of the area and the basic top of the unfilled area.The break position of the basic top rock beam in the unfilled area is obtained.