Research On Rockburst Precursor Information And Rockburst Prediction In Deep Mining

Based on the unloading of deep mining rock masses,this paper studies the energy evolution of limestone unloading and the precursor laws and acoustic emission precursor information.The mechanized panel at the 1261 m stage of the No.8 orebody in the Qilinchang mining area of the Huize lead-zinc mine in Yunnan is studied upwards.The road filling method is the engineering background,and the method of numerical simulation is used to study the stress migration and displacement change law of the stope and surrounding rock during deep mining,and the rockburst tendency of the stope and surrounding rock is predicted,and the following research results have been obtained:(1)Limestone unloading energy evolution and precursor law: When rock is unstable and damaged,elastic energy will drop rapidly,dissipated energy will rise sharply,and energy pressure drop response ratio will change from a large fluctuation state to a quiet period.These characteristics can be used as Precursor information of rockburst.(2)Limestone unloading acoustic emission precursor information: the acoustic emission cumulative ringing count,cumulative energy,RA value,acoustic emission information entropy,and acoustic emission damage are used as precursor identification indicators.These five precursor identification indicators are all before the rock ruptures.Become extremely active,showing a trend of substantial increase.These features can be used as precursors of rockburst.The influence of confining pressure and unloading rate on the precursors of rock rupture has been studied,and it is found that the increase of unloading rate will lead to changes in various precursor identification indicators.The degree is more severe,and each index completes a sudden increase in a short time before the rock ruptures;the increase of confining pressure will cause the time of abnormal sudden increase of each precursor discriminant index to become later,at the same time,the sudden increase lasts longer and the degree of severity decreases.The precursor response coefficient is established.The acoustic emission RA value appears the earliest when the rock is broken,and the precursor response ability is the strongest.The other four precursor discriminant indicators show a fluctuating state of rock fracture recognition with different loading paths.It is necessary to check each precursor The comprehensive analysis of the identification indicators can better capture the precursor information of rockburst.(3)Research on the instability,fracture and rockburst prediction of the deep rock mass in the Huize lead-zinc mine: The 1261 m stage of the No.8 ore body in the Qilinchang mining area of the Huize lead-zinc mine was carried out based on 18 points of the mechanized panel upward approach filling method.Layer excavation simulations have found that there are certain stress concentrations and deformations in each layered roof and surrounding rocks of the upper and lower walls.Based on the rock burst criterion,it is predicted that strong rock bursts may occur in the upper left corner of the roof of the middle section of the ore body and surrounding rocks of the upper and lower walls.