Rock Burst Mechanism And Its Control Methods During The Deep Mining

After years of exploitation,currently the phosphate rock in the shallow layer of China’s phosphate mine has been mined out.Most of the proven phosphate ore are gently dipping medium thickorebody buried in the depth of 300 m below,such as the deep phosphorus ore bodies in the northern part of Yichang,Hubei.Most of these newly discovered billions of tons of phosphate rock are buried in the depth of 500 to 700 m,a few even deeper than 1000 m(a few even more than 1000m).Inthe process of resource exploration and construction of new mines,the high ground stress phenomenon is obvious,and there are serious rock burst in many mines.In the past,there arefew rockburst in the superficial exploitation of phosphate rock,which makes rock burst a new problem to be solved in the deep phosphate rock mining.Therefore,based on the engineering background of Wawu IV ore block of Hubei,Xingfa group,this paper systematically studies the mechanismof rockburst in deep phosphate rock mining,find out the reasons of rock burst,and evetually put forward governance plan of rock burst.In order to study the phosphate rock in deep mining of rock burst mechanism and its prevention measures,carried out the following work: 1.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;2.the detailed geological data and useful information of the Wawu IV ore section are obtained through field survey.And observing the phenomenonof rock burst on the spot.Counting the times of rock burst and selecting the representative samples of rock;3.Through the indoor uniaxial and triaxial tests,the basic physical and mechanical parameters and the stress-strain curve are obtained.At the same time,the microscopic monitoring of rock interior is carried out by acoustic emission,and the rock burst tendency and microcosmic integrity of rock samples are evaluated;4.getting the distribution law of energy and stress through the simulation of on the top floor and seam by use the FLAC3 D.And the phenomenon of rock burst was explained;5.through IV mine field of rock,put forward the effective and feasiblecontrol scheme.Through the study of rock burst,we can get the following conclusions:1.with the approaching of the face during the opposite direction of mining,the number of rock burst and its power are increasing gradually;2.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;3.through the simulation we can find that the roof has the phenomenon of stress concentration and the trend of downward displacement after excavation,but the wall and the floor were not exceed.Thus,rock burst easily occurs in the roof after excavation;4.proposed from the excavation layout,blasting,support,safety management and other aspects of specific measures to prevent rockburst.