Study on the selection and mechanical properties of bearing plate of rock bolt under dynamic and static loading
In deep coal mine roadways prone to rock bursts,the plates of rock bolt are suscepti-ble to deformation and failure under combined dynamic and static loads,leading to support system failure.In view of the above problems,a self-developed drop hammer impact testing machine was modified by adding a dynamic-static load combination testing device.Mechanical performance tests were conducted on seven commonly used plate sizes in coal mines,resulting in deformation patterns and time-history curves of mechanical properties.The effects of impact energy,static load,planar dimensions,and thickness on the mechanical performance of plates were analyzed.The results show that under dynamic,static,and combined loading,the plates experienced processes of arch height reduction,corner lifting,and arch base area reduction.Under static loading,the maximum load displacement increased with planar dimension,and maximum load capacity increased with plate thickness.Under dynamic loading,peak impact force on the plate was significantly higher than under static load.As impact energy increased,both the peak impact force and deformation of the plate increased.Plates with larger planar di-mensions experienced longer impact durations,with peak impact forces ranging from 500 to 600 kN,and impact energy absorption decreasing from 5.25 kJ to 3.50 kJ.Thicker plates showed shorter impact durations,with peak impact forces increasing from 233.26 kN to 467.16 kN,and impact energy absorption increasing from 1.75 kJ to 5.50 kJ.Under combined dynamic and static loads,the energy absorption capacity of a 150 mm×150 mm×10 mm plate increased by more than 20％,and the reasonable static load applied to the plate ranged from 98.00 to 110.25 kN.These findings provide a reference for the selection of bearing plates for rockburst roadways.
plate of rock boltselection of bearing platecombined of dynamic and static loadsreasonable static load
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