Review on the Research Progress of Dynamic Failure Response of Coal-Rock Combined Body
At present,coal resources have entered the stage of deep mining.As the mining depth deepens,the frequency and intensity of rock burst occurrence have increased significantly.Focusing on mine rock mechanics and other issues in rock burst prevention and control,many scholars have carried out a large number of systematic basic research from the perspective of coal-rock combinations.Firstly,the mechanical properties of coal-rock combination under the influence of different factors are introduced.The compressive strength,tensile strength and elastic modulus of coal-rock combination are between coal and rock components,and are more inclined to the mechanical properties of coal components;The characteristics of energy accumulation and energy release of coal-rock assemblies under different conditions are summarized.The loading stage of coal-rock assemblies can be divided into three stages:rapid accumulation of strain energy,slowing down of strain energy growth and rapid release of strain energy.The accumulated energy before the peak and dissipated energy after the peak increase with the increase of com-pressive strength,loading rate,and confining pressure;The effects of rock strength,coal-rock hardness difference,energy differ-ence,coal-rock ratio,inclination angle,loading rate,and external loading conditions on the impact effect are analyzed.The grea-ter the rock strength,the greater the hardness difference between coal-rock,the greater the energy difference,the greater the coal-rock ratio,the greater the inclination angle of coal-rock,and the higher the loading rate,the stronger the impact effect and the more severe the impact phenomenon;The characteristics of acoustic emission energy,ringing count,total number of acoustic emission and other characteristics of the failure process of coal-rock assemblies are studied.When coal-rock assemblies are loaded,the acoustic emission signals have obvious phased characteristics and can be divided into stationary areas,active areas and explosive areas.Acoustic emission activities can be used as an indicator to evaluate the damage state of coal-rock assem-blies;The failure forms and instability mechanisms of coal-rock assemblies under different conditions are summarized.The coal-rock assemblies accumulate a large amount of energy under load,and more energy is accumulated in coal components,which plays a leading role in the destruction of the assemblies.The energy in the rock components plays a certain accelerating and promoting role in the destruction of the assemblies;Finally,the failure mechanism of the rock components of coal-rock assem-blies and the interface effect of coal-rock are discussed,and it is pointed out that the mechanical properties and impact effects of coal-rock assemblies under high osmotic pressure,high temperature conditions,and strong dynamic load disturbances are the key research directions of coal-rock assemblies in the future.
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