Research On Failure Characteristics Of Mining Roadway In Qianqiu Coal Mine Under Rock Burst Condition

The coal and rock mass near the mine mining space is in the higher stress state and dynamic loading,it is very easy to induce the rock burst.Taking the 21221 working face of Qianqiu coal mine as the background,this paper applies the method of theoretical analysis,similar simulation test and numerical simulation to study the response law of surrounding rock of mining roadway under impact and ground pressure.In this paper,the geological characteristics of Qianqiu coal mine and the accident of rock burst in the past years are analyzed.The main reasons for the rock burst are as follows:Structural influence,fracture instability and mining disturbance of overlying thick breccia.The results of the study show that the dynamic load of local rotation and collapse of the mega breccia is the main reason to induce the rock burst in the 21221working face.Taking the 21221 working face of Qianqiu coal mine as the background,The deformation characteristics and instability mechanism of the surrounding rock of the mining roadway under the joint action of support pressure and impact load are studied by the method of similar simulation test.The surface displacement,acceleration,the development degree of surrounding rock fracture and the stress of surrounding rock are monitored,and the displacement,stress and acceleration time history curves are drawn.To study the failure law of the mining roadway under the hammer attack.The results show that under the impact load,the roadway’s roof and baseplate move close to 7.4mm,and the distance between the two gangs is 7.7mm.The stress around the roadway presents an asymmetrical distribution,and with the increase of impact energy,both the acceleration peak and the stress peak increase.Large,with 108J impact energy,the peak left acceleration peak reached 102.6m/s~2,and the horizontal stress peak reached 0.16MPa.Finally,the numerical simulation method is used to study the response law of the mining lane under the action of impact dynamic load:under the action of dynamic load,the surrounding rock of the roadway will be deformed instantaneously,and with the increase of impact energy,the speed and acceleration will increase to varying degrees.With the impact energy of 10~7J,the impact velocity of the roof of the roadway reaches 3.3m/s,the acceleration reaches 410m/s~2,and the peak stress of the roof increases to 8.8MPa;when the roadway is impacted,the roadway exhibits deformation as the width of the coal pillar increases.As the amplitude increases,the speed and acceleration also gradually increase.By comparison,it is reasonable to determine the width of coal pillars protecting the roadway from 4 to 5m to ensure the stability of the roadway when it is washed.It is of certain significance and practical value to guide the monitoring and control the rockburst.