| In resent years,as the coal mining moving deeper layer,the ground stress increases correspondingly,with the occurrence characteristics of coal seam of the roadway's depth,azimuth and dip during roadway design and layout,also with the restriction of the mine design,which leads to the roadway in the unfavorable complex surrounding rock stress environment,the strata pressure behavior of roadway and the problem of floor heave of roadway became worse,thereby many factors that may affect the safety in production of coal mine are exposed,the safety production of mine have been seriously threatened.Therefore,research on the mechanism of roadway floor heave and the prevention measures has the theoretical and pratical significance for not only the guarantee of safety production of deep mining,but also the enhancement of underground mining operation safety.Based on the test results of surrounding rock condition,in-situ stress and rock mechanics of 1#roadway in S6 mining area of Changcun mine,the mechanism and control measures of roadway floor heave in high stress have been carried out through the mechanics theoretical analysis,similar simulation test,numerical simulation,field industrial test etc.The main conclusions of thesis are listed as follows:(1)Based on the theory of elastic mechanics,the elastoplastic damage mechanics analysis of the surrounding rock body of the excavated roadway under the three directional geostress is carried out by using the knowledge of generalized plan strain and unified strength theory,the equations of elastic and plastic zone and the plastic fracture range of surrounding rock of roadway floor under three directional geostress is derived,at the same time,by means of mechanical analysis conclusion,combined with the analysis of the results of the stress of Changcun mining area in-situ detection,the stability of surrounding rock of roadway floor were analyzed by using a numerical example,reveal the influence of roadway condition,axial principal stress etc on the stability of the roadway floor surrounding rock,and the range of plastic crushing zone and stress value of 1#roadway in S6 mining area of Changcun mine is obtained,that provides a reliable theoretical basis for the research of the roadway floor heave control technology;(2)The surrounding rock body of rectangular roadway is studied as the object,A mechanical analysis model of roadway floor as horizontal beam plate is estabilished according to the assumption of beam in mechanics theory,and the mechanical analysis is carried out on the condition of no support and bolt support,reveal the mechanics mechanism of anchor rod to control the floor heave,simultaneously,by means of the analysis of the mechanical analysis results on the factors affecting the floor heave of the roadway,the key problems of controlling the floor heave of the roadway are obtained;(3)According to the field data of surrounding rock acquired in the roadway,1#roadway in S6 mining area of Changcun mine as the engineering background,the similar sumulation tests were taken to analyze the stress distribution and the deformation and failure characteristics of surrounding rock of roadway floor on the condition that the roadway floor is not supported or adopted bottom anchor,which reveals that the direct causes of roadway floor heave is the floor in the comprehensive stress that has been in a high stress state,and affected by horizontal stress,the floor rock mass of its two base angle was extruded and dislocated,fault zone and the floor is about into 35 degrees,at the same time,by compared analysising the roadway floor is not supported or adopted bottom anchor,similar simulatuion test results and mechanics theory analysis results,the bottom anchor measures taken compared to no support,the amount of floor heave decreased by nearly 49.6%,after comprehensive analysis,it is concluded that similar simulatuion test results and mechanics theory analysis results is basically close;(4)An antiarch combined structure of concrete is put forward to control floor heave,based on the mechanics theory and assumption,the mechanical model of the bolt and concrete antiarch combined structure is established,and its mechanical mechanism is studied,simultaneously,by means of mechanical analysis conclusion,combined with the specific circumstances of 1#roadway in S6 mining area of Changcun mine,the stability of the bolt and concrete antiarch combined structure is analyzed by the analysis example,and the stability conditions equation of the bolt and concrete antiarch combined structure is estabilished;(5)According to the specific circumstances of 1#roadway in S6 mining area of Changcun mine,the floor heave control countermeasures and design of supporting scheme is put forword,based on the bolt and concrete antiarch combined structure stability criterion,the concrete antiarch combined struture is confirmed stable and its design parameters are reasonale,meet the safety requirements,the supporting scheme is analyzed by numerical simulation,it is shown that the supporting structure is not exceeding the limit load,and the amount of floor heave is 135mm,field industrial experiment shows that the bottom anchor actual floor heave is 182?194mm,the field test results are close to the results of similar simulation test(243.93mm)and mechanical analysis(274 mm),the actual floor heave is 135?142mm by anchor concrete antiarch combined structure to controlling floor heave,the field test results are close to the results of mechanical analysis(106.7mm)and similar simulation test(135m m)?At the same time,we find that the floor heaves is reduced nearly 73%by the bolt and concrete antiarch combined structure to controlling roadway floor,and supporting structure is stable,the control of floor heave of 1#roadway in S6 mining area is completed. |
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