Study On The Overlying Strata Deformation And Mine Pressure Evolution Law Of Gangue Filling Mining In No.5 Coal Sem Of Tangshan Coal Mine

Gangue filling mining,which has characteristics of good safety,higher recovery rate and environmental friendliness,is one kind of green mining technologies.This mining technology can effectively solve the "three under"(coal seam under the building,the railway and the water)problems and heaping waste in aboveground.The research of overlying strata deformation and mine pressure law is essential for the application of gangue filling mining technology.Therefore,this paper uses the methods of laboratory test,numerical simulation,theoretical analysis,and field monitoring to reveal the laws of overburden deformation and pressure behavior under gangue filling mining condition.The main conclusions are as follows:(1)According to the detection results of roof drilling of the gangue filling face,the broken roof can be divided into three kinds of structures.The mechanical model of roof elastic thin plate was established.The roof of F5001 working face is layered structure.The thickness of the first roof is 3.195m,the maximum tensile stress is 11.87MPa;the thickness of the second roof is 7.578m,and the maximum tensile stress is 9.61 MPa.(2)According to the engineering geological conditions of F5001 working face,FLAC3D software was used to compare and analyze the stress field,deformation field and plastic failure range of overlying strata between the gangue filling mining face and caving mining face.Simulation results show:the failure height of overlying strata decreases by 71.7%,and the expansion rate of plastic zone slows down;the maximum roof subsidence decreases by 35.7%,and the stress value of roof and the influencing range of abutment pressure decrease.(3)Field monitoring results show that the gangue filling mining can effectively control the weighting frequency,weighting intensity and the influencing range of abutment pressure compared with caving mining.The roof weighting step increases by 74%,the weighting intensity decreases by 9.2%and the influencing range of abutment pressure decreases by 44%.In addition,the values of roof separation and rib separation decrease 28.6%and 42.9%,respectively.