Experimental Study On Dynamic And Static Mechanical Properties Of Bearing Plate Of Rock Bolt

Deep mining is often accompanied by rock burst accidents.Rock burst roadway are different from ordinary roadway,and they are subjected to high static load and frequent impact.Roadway support is the last barrier to control rock burst in roadway,and reasonable support structure is the basis to ensure the safety of roadway space.As one of the core components of the bolt,the mechanical properties of the supporting plate have a great influence on the supporting effect of the roadway.In this paper,the arch plates commonly used in coal mines are taken as the research object,and the theoretical analysis and laboratory tests are combined.With the help of JAW-1500microcomputer-controlled electro-hydraulic servo testing machine and drop hammer impact testing machine,the deformation law,impact time-history curve,displacement time-history curve and energy absorption characteristics of plates with different sizes under static load,dynamic load and combination of static and dynamic load are studied,and the mechanical properties under cyclic impact are determined.The reasonable selection and static load of bolt supporting plate in rock burst roadway are obtained,which provides reference for the selection of bolt supporting plate in rock burst roadway.The following main research results are obtained:(1)The stress model of the plate is established,and the relationship among impact energy,impact load and arch height deformation is established,and the influence of structural parameters of the plate on the impact load is analyzed.(2)Under the static load,with the increase of the two dimensions and thickness of the bearing plate,the maximum bearing capacity and corresponding displacement of the bearing plate gradually increase.The two dimensions of the bearing plate has a great influence on the maximum bearing capacity displacement,and the thickness of the bearing plate has a great influence on the bearing capacity.Under the static load,the two dimensions of the bearing plate which is 150 × 150 mm and 200 mm × 200 mm is preferred,and the thickness of 10 mm and 12 mm is preferred..(3)Under the impact load,with the increase of impact energy,the peak impact force,maximum deformation and plastic deformation of the bearing plate gradually increase.With the increase of the two dimensions,the peak impact force of the bearing plate gradually decreases,and the maximum deformation amount and its action time in the elastic-plastic deformation stage of the sample,plastic deformation amount and the deformation speed gradually increases.With the increase of thickness,the peak impact force of the bearing plate gradually increases,and the deformation resistance of the sample is gradually reinforced,and the maximum deformation in the elastic-plastic deformation stage and its action time,plastic deformation amount and the deformation speed are decreasing.(4)Under an impact load,the impact energy of the bearing plate progressively reduces with an increase in the protected surface area and gradually increases with an increase in the thickness.The peak value of the dynamic load impact force and deformation rate is larger than the static load when the sample’s arch height achieves the specified deformation criteria.The two dimensions of the bearing plate under dynamic stress which is 150 × 150 mm and 200 mm × 200 mm is preferred,and the thickness of 10 mm and 12 mm is preferred.(5)Under the combined action of dynamic and static loads,the bearing plate’s rigidity is increased and the total action time is stable,and the overall action time is relatively stable.The reasonable static load of the support plate is 98 k N～110.25 k N.(6)High-energy impact deformation is the major cause of the plate damage.The cumulative deformation,peak impact force,deformation speed,and energy absorption of a high-energy hit of a plate are greater than those of a low-energy cyclic impact as impact energy increases.The deformation of the sample steadily reduces as the number of impacts rises,the peak impact force initially rises and then falls,and the energy absorption properties are definitely improved.Following the application of the static load,the bearing plate exhibits increased rigidity,good stability,a small difference in action time,a peak impact force of the sample that is higher than that of the dynamic load test,and deformation amounts and rates that are lower than those of the dynamic load test.