Research On Influence Mechanism Of Open Deep Hole Blasting On Grouting Curtain And Vibration Control Method

Grouting curtain is a common method of mine groundwater closure and prevention.However,the blasting mining of the mine,especially near the blasting mining of the grouting curtain,will degrade all kinds of mechanical properties of the grouting rock mass,and then reduce the ability of the grouting curtain to groundwater closure.Therefore,it is necessary to study the influence mechanism of blasting vibration on grouting curtain and determine the reasonable blasting vibration control method and safe mining distance.Based on Guangxi China Resources Cement Sag Mine Water Control Project,this paper systematically studies the influence mechanism of blasting vibration on grouting curtain.The mainly discusses content are as follows:(1)The superposition principle and characteristics of seismic waves in small difference blasting of group holes in sag mines were studied,the modification method of Sadovsky formula for small difference blasting of group holes was deduced,and the modification method of Sadovsky attenuation formula was proposed based on the superposition calculation of vibration signals of different single hole blasting,and the programming calculation and analysis were carried out using MATALB software.The modified Sadovsky attenuation formula and charge amplification coefficient are obtained,which provide theoretical basis and analytical method for field test and other related researches.(2)According to the actual working conditions of the site,the model was established,and LS-DYNA software was used to carry out numerical simulation calculation on the site blasting,and the dynamic response characteristics of the grouting curtain in the blasting construction process near the grouting curtain of the sag mining mine were studied.Numerical simulation produces a correlation between the maximum speed peak in the curtain and the peak speed peak on the top of the curtain and the safety criterion for the maximum speed jump of curtain vibrations.Numerical simulation produces a correlation between the maximum speed peak in the curtain and the peak speed peak on the top of the curtain and the safety criterion for the maximum speed jump of curtain vibrations.(3)The field monitoring study on the vibration effect of deep hole blasting was carried out,and the attenuation law of peak vibration velocity of blasting vibration was studied.The modified Sadovsky attenuation formula was used to fit the field data,and the attenuation law of peak vibration velocity of mine blasting measuring point was obtained.The vibration velocity image and elevation amplification effect of particle near the grouting curtain are analyzed comprehensively,which provides a theoretical basis for the calculation of blasting safety distance.(4)Considering the influence of blasting vibration frequency and vibration duration on grouting curtain,particle velocity image of test data,and the main right to suppress the frequency of the vibration signal,the right to distribute the frequency of the vibration signal and the characteristics of the duration of the flashes on the curtain shall be examined and an appropriate method of control of the vibrations with respect to the group exposure of the apertures shall be proposed.(5)In the application of blasting vibration control in sag mine of China Resources Cement Pingnan Company,according to the calculation principle of sadolowski attenuation formula correction method,the vibration superposition effect of different delay time between holes is calculated by using MATLAB software,and the optimal delay time between holes and blasting safety distance are obtained.Combined with the control of the maximum single hole charge of blasting source,the control of blasting vibration duration and the control of propagation path,the safe blasting scheme of grouting curtain was determined.Combined with blasting vibration monitoring,macroscopic investigation and water level and quantity monitoring methods,a closed-loop vibration control method based on dynamic information construction is proposed,which ensures the safe construction of the grouting curtain and the normal mining operation of the mine,and creates good economic and social benefits for the Pingnan mining area.