Characteristics Of Acoustic Signal In Failure Process Of Full Tailings Cemented Backfill

As the concept of "green mines" slowly gains popularity,more and more mines use the backfill mining method for mineral mining.In the backfill mining method,both the roof and the pillars are important load-bearing units.The backfill is in the mine.Whether the mining is stable or not is directly related to the life safety of the mine personnel.Scientific and effective monitoring and prediction of the stability of the filling body has become an important application basic frontier subject to be solved urgently.Based on this,this article is based on the Jiangxi Province Postdoctoral Research Project(2020KY39)to study the acoustic emission and infrasound signal characteristics of the complete tailings cemented backfill failure process under uniaxial compression.The relationship between the uniaxial compressive strength of the filling body and the initial wave velocity is studied,the acoustic emission and infrasonic wave signal characteristics generated during the filling body's destruction process are analyzed,and the acoustic characteristic signal of the precursor of the filling body's failure is mainly studied,and the acoustic emission and infrasound wave are discussed.The relationship between the signal and the curing age of the filling body and the ratio of lime to sand.The main results are as follows:(1)The uniaxial compressive strength of the filling body is positively correlated with the curing age and the lime-sand ratio.The uniaxial compressive strength of the filling body has an exponential function relationship with the initial wave velocity V(2)The number of acoustic emission events of the filling body in the compaction stage is relatively small,and the fractal dimension of acoustic emission events shows a slight upward trend;the number of acoustic emission events during the crack propagation stage increases,and the fractal dimension of acoustic emission events shows up and down changes;When the destruction is approaching,the number of acoustic emission events suddenly increases,while the fractal dimension of acoustic emission events continues to drop to the lowest value.(3)When the stress level is 0?10%,the accumulative energy rate of infrasonic waves is relatively high;when the stress level is 10%?50%,the accumulative energy rate of infrasonic waves is relatively stable;the cumulative energy of infrasonic waves increases suddenly when the damage is approaching.(4)The infrasonic sub-dominant frequency signal of the filling body is mainly distributed in the frequency range of 0.1?5Hz and 10?15Hz in the compaction stage.As the stress increases,the secondary main frequency signal gradually changes from being concentrated in 2 frequency bands to being concentrated in 4 frequency bands.Before the destruction,the signal in the 0.1?10Hz frequency band of the secondary main frequency gradually disappeared and shifted to the 10?20Hz frequency band.(5)Under the same curing age,with the increase of the lime-sand ratio,the stress percentage corresponding to the sudden increase point of the infrasound cumulative energy rate and the lowest point of the fractal dimension of the acoustic emission event gradually decreases.The stress percentage corresponding to the lowest point of the fractal dimension of the acoustic emission event is compared and analyzed.The stress percentage corresponding to the lowest point of the fractal dimension of the acoustic emission event is greater than the point of the accumulated energy of the infrasonic wave.