Study On Characteristics And Control Of Fully Mechanized Mining Face Pressure In A Deep Coal Mine In Tangshan

Coal resources have always been the dominant energy source in China.However,with the decreasing of shallow recoverable coal resources,the vigorous development of deep coal resources will be the inevitable choice for China in the future.Deep coal mine has the characteristics of high ground stress and high rock burst tendency,and the mine pressure behavior is stronger and more frequently.The 3191 E working face of a deep coal mine in Tangshan is used as the engineering background in this thesis.The characteristics of fully mechanized mining face pressure in deep coal mines are systematically studied using theoretical analysis,numerical simulation,on-site mine pressure monitoring,and other methods,and the mine pressure control method of the working face is put forward.The following are the key research findings:(1)The position of key stratum and its fracture step are determined.Through the key stratum theory,the position of the key stratum is determined.Based on the theory of elastic thin plate,a mechanical model for calculating the breaking step distance of key stratum is built.The stress variation characteristics of roof during the advancing process of working face are analyzed,and the breaking step distance of key stratum is obtained,as well as the internal causes of large and small periodic weighting in working face are revealed.(2)A three-dimensional numerical calculation model of the 3191 E working face is established.Combined with engineering geological information,through simulation study,the stress evolution law and plastic failure evolution law of overlying rock under different working face advancing distances,as well as the stress distribution characteristics and plastic failure zone distribution characteristics of roadway surrounding rock,are obtained.(3)The variation of support resistance of working face and stress of coal-rock mass around the roadway were monitored.The mine pressure of the working face is measured and studied.Through the analysis of the monitoring data of the support resistance,the initial pressure law,periodic pressure law and corresponding pressure characteristic parameters of the working face are obtained.Through the analysis of stress monitoring data of coal-rock mass around the roadway,the stress variation law of coal-rock mass around the roadway and the influence range of advanced support pressure on surrounding rock were obtained.(4)The rationality of support working resistance and roadway bolt support parameters is verified.The discriminant formula of the structural form after the key stratum fracture is established,and the calculation model of the working resistance of the support is constructed for the different structural forms after the key stratum fracture,and then the reasonable working resistance of the support is calculated.At the same time,based on the suspension theory,the rationality of the roadway bolt support parameters is verified.Finally,the mine pressure control method of the working face is put forward.