Rock Burst Mechanism And Its Control Methods During The Deep Mining For Phosphate Mine

The mining depth of phosphate mine is shallow in our country.In the past,the phenomenon of rock burst is less during the mining for phosphate mine.The study of rock burst is still in the theoretical stage and its control methods aren't effective enough.But now,the mining depth of Hubei Xingfa Group IV ore section has reached 700 meters and is increasing year by year.Meanwhile,rock burst phenomenon increasingly prominent during the mining for phosphate mine.Thus,the study of the mechanism of rock burst will be helpful for finding out the rock burst control methods to solve the problem of rock burst on the scene.In order to study the mechanism and control methods of rock burst during the deep mining of phosphate rock,the following work is carried out:first,a summary on the mechanism and laws and evaluation methods of rock burst through collecting a large number of domestic and foreign research results on rock burst.Second,the detailed geological data and useful information of the Wawu IV ore section are obtained through field survey.And observing the phenomenon of rock burst on the spot.Counting the times of rock burst and selecting the representative samples of rock.Third,basic physical and mechanical parameters and stress-strain curves are obtained through uniaxial test and triaxial test.Fitting the curves and the rock burst orientation was evaluated.Fourth,getting the distribution law of energy and stress through the simulation of on the top floor and seam by use the FLAC3D.And the phenomenon of rock burst was explained.Fifth,the effective and feasible of control methods were put forward aim at the reason for the rock burst of IV ore section.Through the study of rock burst,we can get the following conclusions:first,with the approaching of the face during the opposite direction of mining,the number of rock burst and its power are increasing gradually.Second,the roof and ore body are belong to the hard brittle rock mass.The ability order of dump energy is the roof,ore body and floor.The roof has the tendency of rock burst.Third,through the simulation we can find that the roof has the phenomenon of stress concentration and the trend of downward displacement after excavation.Its value is 0.22cm.Meanwhile,the energy of the roof had exceed 1×10~5J,but the wall and the floor were not exceed.Thus,rock burst easily occurs in the roof after excavation.