Study On The Explosion Tendency Of Different Depth Of Limestone Based On Acoustic Emission Parameters

Buried in deep or medium deep metal mine,rock-burst is more and more likely to happen,because of the growing geostress.The technical problem of mining increase,because of the high geostress in deep mining.According to mining technical condition of deposit and ore-bodies in the mines,to avoid detriment caused by rock-burst,economic and reasonable measures was selected to realize safe and efficient mining.More and more metal mine enterprise desire to solve it to promise the sustainable produce.Because of crustalmovement,strain energy of rock mass buried in deep metal mine gathered together,leading to great initial stress.Gathered strain energy burst out,which call rock-burst,in the process of deep stoping.On the one hand,rock-burst is relevant to initial stress field.On the other hand,it is also relevant to distortion and energy storage characteristic in the loading procedure.The monitoring technique of rock mass acoustic emission catch the instantaneous elastic waves generated in the destruction procedure.So the results of AET as basis of rock crack is research emphasis in the rock mechanics area.Beneficial conclusions is obtained with rock damage of Acoustic emission characterization of rock damage.But it is unfrequent using AET to predict rock-burst.This research use elastic energy index to value rock-burst vulnerability.Experimentalize rock-burst vulnerability with limestone at different depth,The stress-strain is obtained in the loading unloading process.Analyzing the change rule of AE accumulative energy along with time,the characteristic of rock-burst vulnerability is obtained,revealing AE response characteristic of limestone’s rock-burst vulnerability.By analyzing AE accumulative energy gradient,accumulative energy ratio Ek which equal the ratio of AE accumulative energy gradient in the loading unloading process and in turning point of loading unloading process was defined.It turn out that:(1)With increasing depth,uniaxial compressive strength is trending to increase.It provide advantage for rock-burst.Also it demonstrate that rock-burst is more and more likely to happen.It has also showed that rock-burst is closely relevant to the depth.(2)In the loading process,with increasing occurrence,storage capacity of strain energy is increasing.In the unloading process,with increasing depth,the increase of AE accumulative energy trend to be smaller.So distinct difference of different depth’s limestone AE accumulative energy is recognized.(3)With the depth increasing,the area of hysteresis curve gradually decrease in the loading unloading of limestone.It illustrate that storage capacity of strain energy is being enhanced,which is major reason for inducing rock-burst.Rock-burst vulnerability is more and more large: testing rock-burst vulnerability with different depths of rock,analyzing elastic strain energy index Wer in the loading unloading process,it conclude that elastic strain energy index trend to be increase with depth increase and Rock-burst vulnerability trend to be obvious.(4)Analyzing AE accumulative energy in the loading unloading process,AE accumulative energy of limestone whose Rock-burst vulnerability is not obvious is bigger than whose Rock-burst vulnerability is obvious.And increasing range of AE accumulative energy is gradually small,with Rock-burst vulnerability increasing.There is bumping up of Rock-burst vulnerability at the turning point of loading unloading process.(5)Analyzing AE accumulative energy ratio in the loading unloading process,accumulative energy ratio Ek was defined.When Ek is greater than 1,it illustrate that rock-burst vulnerability is not obvious.On the contrary,rock-burst vulnerability is obvious.And if the value of Ek is quiet in the loading unloading process,rock-burst vulnerability is more obvious.So accumulative energy ratio Ek reached by experiment can provide reference frame for deep rock’s rock-burst vulnerability.