Research And Application Of Acoustic Emission Characteristics During The Damage Process Of Mine Cemented Backfill

At present,metal mining with the deepening of the deepening of mining,ore recovery grade continues to improve,filling mining method has been widely used.With the large-scale mining equipment,continuous,in order to facilitate the pressure control and management,underground metal mining has been the continuous mining mining development direction.At the same time,with the occurrence of ore body conditions become complex,the ground pressure increases sharply,the weak rock formation,the accumulation of solid waste and other problems,resulting in ore body recovery is increasing,and accompanied by a series of safety production risks,In the underground mining complex mechanical environment(such as blasting vibration,exposure surface changes,overburden pressure with the plate mining sequence changes,etc.),once its damage or instability,the adjacent mining will form a serious threat to safe mining The The study of mechanical properties and damage mechanism of cemented filling in complex environment is an important basis for the optimization of filling material selection,optimization and stability of filling material.Therefore,the damage characteristics of the filling body can be studied and the damage of the filling body can be made Accurate and timely prediction is imperative,but also urgent.In this paper,the damage characteristics and acoustic emission characteristics of the cemented cementation under the cyclic loading are studied according to the stress characteristics of the cemented loading.The purpose is to reflect the engineering mechanics path and to reveal the damage mechanism of the filling body by acoustic emission,The relationship between the ratio of tailings and the damage parameters was established.And different fractures dimension of acoustic emission parameters are used to characterize the internal damage of tailings cementation,which provides the basic research basis for the bearing process analysis and destabilization prediction.In this paper,the tailings and unloading test and the acoustic emission test of the tailings of the Daxingshan copper mine are designed.The results show that:(1)The total strain ? and the plastic strain ?p decrease with the increase of the number of cycles when the tailings are filled and unloaded at the same stress level.The elastic strain ?e increases with the increase of the number of cycles.The total strain?,the plastic strain ?p and the elastic strain ?p increase with the increase of the number of cycles when the cyclic loading and unloading is carried out at the incremental stress level.The elastic modulus E1 decreases with the increase of the cycle time,and the loading deformation modulus E2 is not the same.When the specimen is unloaded and unloaded at the same stress level,the loading deformation modulus E2 of the filling specimen And the loading deformation modulus E2 increases abruptly when the stress level is increased to a new height.(2)the filling of the specimen loading stage is the elastic strain energy storage stage,the stored energy is released when unloaded slowly,and when the stored elastic strain energy is greater than the critical value,the stored elastic strain energy will not be filled And the irreversible dissipation energy will increase with the increase of the number of cycles "slow ? accelerate ? rapid" growth trend,the increase of irreversible dissipation energy will reduce the filling of the body Mechanical properties,so the destruction of the filling body is the result of the release and dissipation of the energy.The energy dissipation causes the filling body to deteriorate and the mechanical properties are reduced,and the energy release causes the overall failure of the filling body to be destroyed.(3)The damage evolution equation of the filling body based on the damage energy release rate can better reflect the damage behavior of the filling body and have a good correlation with the filling ratio of the filling body.(4)From the acoustic emission ringing count and the energy count,it can be seen that the filling body also has the Kaiser effect;(5)The failure of the filling body is a dimensionality reduction process.The sharp decrease of the fractal dimension indicates that the large-scale destabilization failure of the filling body is approaching.Therefore,the fractal dimension.The sharp reduction of the fractal dimension and the amplitude fractal dimension is the criterion for the imbalance of the filling body.The best fractal dimension is the amplitude fractal dimension,and the damage effect of the filling body is better by using the acoustic dimension of the acoustic emission amplitude.(6)The quantitative relationship between the acoustic emission cumulative energy and the damage parameters and the mix ratio of the tailings cemented loading under cyclic loading and unloading conditions was established.Finally,the prediction model of the damage model of the filling body based on the acoustic emission cumulative energy was obtainedThe research results of this paper have important theoretical significance to explore the mechanism of damage and danage of tailings cemented filling,and it has a strong application value and guiding significance for the prediction and prediction of damage and failure of mine filling.