Theoretical Research On Hydraulic Support Type Selection For Steeply Inclined Coal Seam Subsidence Pseudo-inclined Fully Mechanized Mining Face

Steep seam reserves in our country is very rich,and the distribution range is wide,with the comprehensive mechanized production level and face the improvement of management level,increase gradually in the mining of deeply inclined coal seam,gentle nearly horizontal coal seam mining gradually reduce,but the steep coal seam mining technology have more need to conquer the technical problem.In recent years,many scholars have studied the overburden migration law,ore pressure behavior law,roof structure stability,hydraulic support stability and so on in steeply inclined coal seam mining,and obtained a large number of results.Based on the engineering background of N2612 working face of Fengchun Coal Mine of Chongqing Songzao Coal and Power Co.,Ltd.,this paper makes a systematic study on the overlaying rock migration characteristics and the adaptability analysis of hydraulic support in the fully mechanized working face of inclined pseudo inclined coal seam by using the methods of field investigation,field measurement,numerical simulation and theoretical analysis.Based on the research results,the reasonable selection of hydraulic support for steeply inclined and pseudo inclined working face is studied.The main research results are as follows:(1)Through the experiment,the physical and mechanical parameters in the density and uniaxial compression test of rock,tensile test and shear strength test,the density of rock under natural state,the uniaxial compressive strength,tensile strength,Elastic modulus,Poisson's ratio,cohesion,Angle of internal friction,the N2612 related working face in rock mechanics parameters is obtained,provided the basis for subsequent analysis.(2)The beam model of roof of inclined pseudo inclined working face in steeply inclined medium thick coal seam is established to analyze the broken characteristics of working face roof.The upper horizontal roof breaks in the advancing direction of working face,and then the middle and lower horizontal roofs break one after another,showing spatio-temporal differences.In the inclined direction of the working face,after the fracture occurs at both ends of the roof,the roof at the middle and upper position will fracture first,and a relatively stable hinged structure will be formed along the inclined direction of the roof.(3)Based on the coal strata structure of N2612 working face,the FLAC3 D numerical simulation method was used to study the influence of different advancing lengths on the stress distribution law of working face and the displacement law of surrounding rock in steeply inclined inclined pseudo inclined coal seam mining.(4)Based on the existing research results,the interaction characteristics between support and surrounding rock are analyzed.By calculating the working resistance of the hydraulic support in the support scheme,the reasonable working resistance of the hydraulic support is obtained under the condition of meeting the safety production.The advantages and disadvantages of the two-column shield type and the four-column support shield type are discussed,and the reasonable selection of the hydraulic support in the working face of steeply inclined inclined pseudo inclined coal seam is completed.