Research and Application of Energy Threshold of Coal Instability Failure under Dynamic and Static Loading
One-dimensional and three-dimensional dynamic and static combined loading tests are carried out by using Hopkinson pressure bar,and the energy evolution law of coal fracture process under dy-namic and static combined loading is studied.The energy threshold of coal instability failure under dynamic and static combined loading is determined,and the impact danger zone of 7305 working face in Xinhe Coal Mine is divided.The results show that with the gradual increase of dynamic load stress,the coal body has un-dergone compaction and elastic stages successively.At this stage,the input energy of the coal body is small,and the corresponding absorption energy ratio ξ also increases slowly.However,when the crack of coal body expands rapidly,with the continuous increase of external dynamic load,the absorption energy of coal body increases rapidly,and the absorption energy ratio ξ also increases accordingly.When the macroscopic fail-ure of coal body occurs,the absorption energy ratio ξ reaches the limit value.The limit value of the absorp-tion energy ratio ξ can be used as the indication point of the instability and failure of coal under the action of dynamic and static combined loading,and the corresponding coal absorption energy can be used as the ener-gy threshold of the instability and failure of coal.The quantitative relationship between the energy threshold of coal instability failure and the static load and the external impact velocity under the three-dimensional dy-namic and static combined loading operation is proposed,and the dangerous area of the working face is de-lineated based on the numerical simulation results.This study has certain guiding significance for the pre-vention and control of mine dynamic disasters.
dynamic and static loadingcoalinstability failureenergy threshold
万方数据
维普
