1、 翻翻 译译 部部 分分 英文原文 EME rock burst monitoring in coal mine huafeng(Dou lin ming，china university of mining and technology,Xu fangjun,Zhang xiufeng，huafeng mine,shan dong,china)Abstract The electromagnetic emission is caused by the inhomogeneous variable speed and the deformation of various parts of th
2、e coal and the variable speeding movement of electrical particles during crack expansion.This article is about the EME rules before and after the coal sample failure in 4#coal seam of HuaFeng mine by experiments.some methods to monitor and forecast.KBD5 apparatus has been used to monitor the 4#coal
3、seam which has high danger of burst in Huafeng mine,many times rock pressure were forecasted according to the EME rules.Therefore EME technique can be applied in coal mines.1 EME mechanism of rock burst failure 1.1 EME Mechanism of Rock Burst Failure The research shows that the EME is the result of
4、the deformation and the failure of the loaded inhomogeneous materials,such as coal and rock,and is formed in the variable speeding movement of electrical particles during crack expansion caused by the inhomogeneous variable speed and the deformation of various parts of the coal.Variable deformation
5、of various parts of the variously loaded coal and rock makes the free and escaping electrons move from the high-stress zones to the low-stress zones.At the same time,a lot of charges are covering the coal samples surface,thus coulombs field or low frequency EME comes into being.Before the crack expa
6、nds,there are a great number of charges or electrons on it.After the crack expansion,parts of the coal around the crack contract,meantime the Coulombs field is formed because of the high concentration of electrons are accelerated with EME radiated.EME are ionized.1.2 EME Phenomena and Experiment Res
7、ult of Rock Burst The EME characteristic of HuaFeng coal was described by the experiment in lab.Fig 1 represents the typical curves of the stress distribution,EME impulse distribution and EME amplitude distribution of HuaFeng coal sample,which has high danger of Rock Burst.From the experiment result
8、s we know that EME signals appear in the process of deformation and failure udder loading the various coal and rock.EME amplitude is below a certain value before the brittle failure,while it suddenly increase of loading and the rate of deformation in coal.EME amplitude is below a certain value befor
9、e the brittle failure,while it suddenly increases during the brittle failure of the loaded coal sample.If the 80%of the maximum failure stress of the coal sample is considered as the warning EME value of Rock Burst,then it can be figured out on the basis of EME experiment.The warning EME value of Ro
10、ck Burst of the 4#coal seam in HuaFeng Mine are listed as Tab 1 shows:Tab 1 The warning EME value of Rock Burst Coal seam The stress value of brittle failure/Mpa The EME value of coal failure Maximum Warning value Amplitude/mv Impulse maximum Warning value maximum Warning value 4#16.1 12.9 433 346 6
11、10 488 a.The relationship between EAE load and time of 5#coal sample b.The relationship between EAE amplitude and time of 5#coal sample c.The relationship between EAE impulse and time of 5#coal sample Fig.1 the result of coal sample experiment The experiment results show EME impulse basically increa
12、sed with the increase of loading and the rate of deformation in coal.The higher the stress and the rate of deformation are,the stronger the EME signal is.2 forecastinf of rock burst 2.1 The principle of EME s forecasting Rock Burst The coal on the working face is in an unstable state when its stress
13、 balance is broken after the heading and working space has been formed.There is EME radiated in the process of the rib coals deformation and cracks forming to have a new stress balance,causing the coal to deform and to crack.The higher the stress in the coal is,the stronger the EME value is.The high
14、er the EME frequency is,the greater the danger of Rock Burst is.From the low-stress zone to the high-stress zone with the working face advancement,the EME signal is becoming stronger.In the abutment area,the stress sis the highest,and the deformation of the coal is also great,therefore the EME signa
15、l is the strongest.In the low-stress zone,the EME amplitude decrease and intends to the balance.The EME signal received by isolated way is a collectivity of the ones if both low-stress zone and high-stress zone.When the stress in the monitored zone is high,the EME signal gives the just character of
16、high stress zone,therefore we can use the EME signal to describe the high stress zone and then forecast the Rock Burst.The research of the on-site test and the analysis in theory all shows that the deformation value-(t)vary with EME amplitude and impulse.Before the Rock Burst,the EME value is higher,then it decreases,bur during this period of time the value reaches or exceeds critical value.The change of the EME value and impulse reflects the process of the failures growth.2.2 Methods of the For
