Study On The Influence Of Macroscopic Fracture On Energy Release Of Coal Failure

Rock burst is one of the most dangerous dynamic disasters in coal mine,and the prediction and prevention of rock burst is an important problem in mining engineering.Rock burst is a phenomenon of massive release of energy,and it is an important method to study rock burst through the energy factor.There are a lot of macroscopic fracture in the coal,which have an influence on the strength and properties of coal.Accordingly,the macroscopic fracture should have an effect on the energy of coal,and energy plays an important role in the occurrence of rock burst.Therefore,it is very important to study the influence of macroscopic fracture on the energy of coal failure.In this paper,the influence of macroscopic fracture on the energy in the process of coal failure is studied by theoretical analysis,laboratory test and numerical simulation.It uses theoretical analysis method to study the influence of macroscopic fracture on the energy accumulation and release of coal and rock mass.Applying laboratory test methods to detect the macroscopic fracture in the selected coal samples,then this paper studied the difference of energy storage and release process of coal samples with different macro cracks.The numerical simulation method is used to establish the numerical model of the coal sample parameters in the experiment and studied the energy change of coal under different macroscopic fracture conditions to determine the influence of fracture on coal energy.This paper gets that macroscopic fracture has a dissipative effect on the energy in the process of coal failure,and it gets the energy equation of coal with macroscopic fracture.The test results by NMR and uniaxial compression acoustic emission test show that the energy of the coal sample with multiple fracture and high fracture rate has short accumulation time,long release time,and its smaller energy peak.By using the numerical simulation of FLAC3D.it is found that the energy value of the coal seam under the action of the load is lower,and the energy value of the coal model decreases with the increase of the fracture and the number of fracture.Finally,it is concluded that the macroscopic fracture can cause the energy of coal release,accumulation and the peak energy decrease.