Dynamic Response And Damage Control Technology Of Filling Body Under Blast Loading

With the growing awareness of environmental protection,the advancement of backfill technology,and increased emphasis on safe mining practices,the backfill method has become a crucial mining technique for metal mines.The success of this method relies on ensuring the stability of the backfill body.In metal mines,blasting is the primary means of filling mining and the resulting disturbance is a leading cause of instability in the filling body during the two-step stoping process.To mitigate the damage and destruction caused by blasting in adjacent stopes,this paper is guided by the damage control of the filling body under blasting disturbance.The aim is to effectively control explosion energy and minimize the degree of damage and destruction of the filling body.Therefore,the research work presented in this paper focuses on:(1)The ultra-high-speed digital image correlation experimental system was utilized to investigate the two primary factors that influence backfill body damage,namely,the distance between the blast source interface and the amount of explosive as dependent variables.The system also revealed the evolution law of ore-backfill strain field under the influence of blasting loads.In combination with fractal theory,the study examined the damage distribution characteristics of the backfill body and established a prediction model for backfill blasting damage.The findings suggest that the optimal interface distance of the blast source significantly impacts backfill body damage,and that side hole blasting has a more pronounced effect on backfill body damage.(2)To investigate the impact of side hole blasting on backfill damage characteristics,a side hole blasting model was developed.From a blasting control perspective,the study examined the damage control mechanism of backfill by analyzing delay time,charge structure,and initiation mode.Results indicate that using bottom initiation in the side hole can reduce the strain field strength of the backfill.Moreover,directional detonation free surface,generated by side hole axial shaped charge blasting,can prevent the propagation of explosion energy to the filling body.Building on these findings,the paper proposes the "CLB"blasting damage control technology,which involves a "cutting-looseningblasting" approach.(3)An ore-backfill three-dimensional explosion model experiment was conducted based on the "CLB" blasting damage control technology.The study compared simultaneous initiation and traditional delayed initiation as the control group to analyze the dynamic fracture behavior,surface flatness,vibration response,damage distribution,and blasting lumpiness distribution characteristics of the backfill under different blasting schemes.Results demonstrate that "CLB"blasting technology effectively reduces vibration and damage.(4)The parameters of the constitutive model of ore and backfill were obtained through laboratory experiments and theoretical calculations.Subsequently,a numerical simulation was conducted to establish the ore-backfill three-dimensional blasting numerical model at an engineering scale.The study analyzed the evolution process and quantitative distribution law of the backfill stress field and revealed the deterioration characteristics of the backfill with damage.The results confirmed that "CLB" blasting technology has a positive impact on damage control under an engineering scale.(5)Field conditions were considered when conducting an industrial test to monitor the stability of the backfill body.The study demonstrated the effectiveness of "CLB" blasting technology in reducing vibration and loss,based on the stope blasting vibration response and the deterioration of backfill strength.As a result,the technology holds great potential for practical applications.