Abstract:The crushing range of coal mass is an important evaluation index of loosening blasting.To research the influencing factors of the crushing range of coal mass in single-hole blasting,this paper uses ANSYS/LS-DYNA finite element software to establish a two-dimensional numerical model,in order to study the relationships among factors such as blast hole radius,decoupling coefficient,explosive density,tensile strength and coal mass crushing.The research results show that:the ranges of the crushed zone and the fractured zone increase with the increase of charge radius;with the increase of blast hole charge radius,the ratio of the crushed zone range to the charge radius remains basically unchanged,but the ratio of the fractured zone range to the charge radius decreases gradually;when the decoupling coefficient increases,the range of the crushed zone decreases gradually,and the range of the fractured zone shows a trend of increasing first and then decreasing;when the wave impedance of the explosive is the same as that of the coal mass,the range of the crushed zone is relatively large,and with the increase of explosive density,the range of the fractured zone presents a trend of increasing first and then decreasing;with the increase of tensile strength,both the ranges of the crushed zone and the fractured zone of coal mass decrease,and the variation of the fractured zone range is higher than that of the crushed zone.The research conclusions above have certain guiding significance for the design of presplit blasting parameters in coal mines.

Abstract:Static emulsification process,with the characteristics of high safety,simple operation,energy saving and environmental protection and others,has become the current research hotspot and future development direction of emulsion explosive production technology,with many successful application cases in explosive production line.This study describes several different principles of static emulsification process and their structure of emulsifiers in detail,and,analyzes their feasibility and application prospect in the production of powdery emulsion explosive.The study also points out the problems existing in the application.This study provides ideas for researchers to select and design the static emulsification production line.

Abstract:To meet the requirement for the accurate measurement of explosive detonation velocity,this paper conducts experimental study on charge thickness,sympathetic detonation propagation,and testing methods.Comparative experiments are designed with different charge thicknesses(10,15,20,25,30 mm)and sympathetic detonation distances(1,2,3,5 cm).And,datas from tests with copper tube-protected probes and unprotected probes are collected.Combined with the conversion and differential processing of voltage-time(U-t)characteristic curves,the instantaneous detonation velocity variation curves of explosives are obtained.The research results show that copper tube can effectively avoid detonation interference and significantly improve the reliability of test datas;the detonation wave propagation of emulsion explosives presents obvious fluctuation characteristics with an unstable propagation process,and both the detonation velocity and propagation stability are gradually improved with the increase of charge thickness;the increase of transmission distance leads to a decrease in the instantaneous detonation velocity of the acceptor charge and a significant reduction in the stability of the initial propagation stage.The testing method established and the laws revealed in this experiment can provide key experimental basis for explosive performance evaluation and detonation mechanism analysis.

Abstract:To mitigate the adverse effects of foundation pit blasting on surrounding buildings under construction and residential houses in complex urban environment,this paper combines the actual conditions of the construction site to determine reasonable borehole network parameters,specific charge,and single-stage detonation charge.By adopting integrated technical measures such as delay blasting,vibration isolation trenches,sandbag coverage,and blast mats,the harmful effects of blasting are minimized.Additionally,the NUBOX-8016 intelligent monitoring instrument is utilized to monitor blasting vibrations.Monitoring datas indicates that the delay blasting technique and vibration isolation trenches have a significant effect on reducing blasting vibrations.Compared the measured blasting vibration values with the Sadovsky predicted ones,the blasting vibration is reduced by 43.18%.The protective measures employing sandbags and blast mats effectively control flying rocks and air shock waves,safeguarding surrounding buildings from harmful blasting effects.This study provides a valuable reference for blasting operations in similar complex environments.

Abstract:The emulsion explosive manufacturing technology has gradually developed towards flexible production and automation.In view of the technological upgrade requirement of emulsion explosive production line,this paper introduces the transformation and application of the online quality monitoring system,accelerator recycling device,and charging and packaging system in detail.This transformation not only improves the automation level of the production line and refines the closed-loop quality control model covering the entire production process,but also reduces the number of on-site operators during production.It ensures the stability and reliability of the product quality.Furthermore,it provides practical technical references for the flexible manpower production mode in the emulsion explosive industry.

Abstract:Based on the thermodynamic and kinetic equilibrium disruption effects of emulsion explosives under alpine and negative pressure environment,as well as the initiation and detonation characteristics of the explosive,this study adopts polymer foaming particles(referred to as VACPM)and expandable polystyrene particles(referred to as EPS)as physical sensitizer to research the technology of physical sensitization for emulsion explosives.This study investigates the preliminary relationship among particle foaming size,the detonation velocity,as well as initiation sensitivity of explosives.The results indicate that EPS sensitizing explosives have detonator sensitivity,and the detonation velocity is from 1 986 m/s to 2 473 m/s;when the size of the polymer foam particles sensitizer is from 8.5 μm to 100 μm,the detonation velocity ranges from 4 630 m/s to 5 252 m/s.The manufacturing technology of VACPM,from material selection to process optimization,has become quite mature.And its key properties such as foaming size,uniformity and true density,as well as economic performance,still have greater room for adjustment.Compared with EPS,the VACPM is more suitable for the production and application of emulsion explosives.

Abstract:This paper introduces a method for measuring the charge height of flash detonator based on contour scanning technology,and investigates the effects of different tube lengths,different light source interferences,and reflective surfaces variations on the measurement accuracy of the system,with comparisons relative to manual measurement.The results show that the measurement accuracy of the charge height detection system is unaffected by tube length,with a maximum range of 0.54 mm for repeated measurements of the same sample.When the punch end face is subjected to stains,rusts,and wear,and the maximum variation of the measured values is 0.40 mm.When simulating external light interference,it causes irregular changes in the measurement error of the charge height detection system,with a maximum range of 0.59 mm.The experimental results show that the measurement error of the flash detonator charge height measurement system based on contour scanning technology is lower than that of the manual measurement,indicating that it meets the technical requirements of the detonator production online measurement process.

Abstract:In view of the problems in the packaging process of small-diameter cartridges of industrial explosives,such as artificial auxiliary material arrangement,low production capacity,inaccurate counting of cartridges,and collapse during stacking of products,this paper studies the key technology and equipment such as intelligent material arrangement,counting and stacking,robot intelligent grasping,bag opening and forming,and,collecting and packaging.The results show that the developed intelligent packaging system for small-diameter cartridges of industrial explosives has characteristics of smooth processing,stable running,packaging capacity not less than 8 t/h,compact and regular packaging,and easy stacking.Furthermore,it realizes no fixed operators on the production site.

Abstract:Dry ice is of high security because it does not involve high pressure gas and hazardous chemicals.And,it has a great advantage in cost.Therefore,it is of great significance to study the effect of dry ice on blasting effect.Based on the dry ice phase-change blasting theory,this research comprehensively utilizes engineering blasting techniques combined with actual on-site production to experimentally study the blasting effects of sandstone under conditions of interval charging containing dry ice at proportions of 0%,20%,25%,and 30%,respectively.Additionally,vibration measuring instruments are used to measure the blasting vibrations with and without dry ice.The research findings indicate that as dry ice increases,the blasting and throwing effect of sandstone ore layers gradually get worse,the rock fragmentation size significantly increases,and the large lump rate notably rises.Therefore,the optimal usage must be determined upon production needs in practical applications.Based on field conditions and economic benefits,the optimal dry ice ratio is set to 25%.When the charging total length remains constant,after adding dry ice,the maximum blasting vibration velocity in Blasting Area 2 decreases by 0.173 cm/s compared to that in Blasting Area 1,with a reduction of approximately 51.5%,which significantly reduces the blasting vibrations generated by blasting operations.

Abstract:The stability of mixed emulsion matrix is a crucial indicator for evaluating the performance of mixed emulsion explosives.This paper introduces a new method for testing the stability of mixed emulsion matrix—the vibration method.The stability of mixed emulsion matrix is tested by this method and the results are compared with those obtained by the natural storage method.Moreover,the reliability and accuracy of the vibration method are analyzed.Experimental results indicate that the vibration method is simple and fast,and,it can better simulate the stability of the mixed emulsion matrix during transportation and use,with a wide applicability.Furthermore,it shows a strong correlation with measured value by the natural storage method.This method proposes a simple,fast,accurate,and practical way to test the stability of mixed emulsion matrix,which has important guiding significance for the production of mixed emulsion explosives.

Abstract:In order to reduce the harmful effects of blasting,improve the energy utilization rate of explosives,and solve the problems in traditional interval charging techniques such as insufficient strength of barrier material,inadequate sealing,and the failure of the lower charge section to detonate due to pressure,a deep-hole in-hole bag-hanging segmented charging technology is proposed.This paper introduces the characteristics and applicable scope of the in-hole bag-hanging interval charging technology,and conducts tests in an open-pit mining project.Through analysing and comparing the blasting effect,obtained by the this design scheme and the original one,it is found that the boulder rate decreases by 52%,blasting vibration reduces by 12%,and the specific charge of explosives decreases by 8%,indicating a significant improvement in blasting effect.

Abstract:Aiming at the issue of high powder ore rate in open-pit limestone aggregate mine,this paper estimates the scope of the crushed zone based on the explosive matching principle with reasonable control.Meanwhile,by adjusting explosive properties,the explosive theoretical parameters suitable for controlling the crushed zone in limestone aggregates are calculated.Additionally,three finite element models are established by numerical simulation technology,and,the differences in powder ore rates after blasting with explosive of different theoretical parameters are analyzed.The results indicate that as the density and detonation velocity of the explosive increase,the powder ore rate shows a significant upward trend.On the premise of balancing powder ore rate and large lump rate,it is found that ANFO explosives with low density and low detonation velocity can effectively reduce the powder ore rate.And,combined with field test demonstration and screening,it is found that the powder ore rate of model 1 with ANFO explosives of low density and low detonation velocity is obviously reduced after blasting,which is more suitable for blasting operation in limestone aggregate mine.

Abstract:To explore the effect of ambient temperature on the water resistance of industrial electronic detonators,tests are conducted after storage under three ambient temperature conditions:low temperature,high temperature,and thermal shock.The test results indicate that low temperature has no effect on the water resistance of industrial electronic detonators.However,after exposure to high temperature,the injection-molded plug of the industrial electronic detonator shrinks in radial diameter when contacting with water,which reduces the sealing strength against water.It leads to short circuits or damage to the electronic control module,resulting in failure to be detonated properly.Furthermore,as the temperature increases,the radial shrinkage of the injection-molded plug intensifies,thereby increasing the probability of detonator failure.The rapid temperature changes characteristic of thermal shock exacerbate the shrinkage and deformation of the injection-molded plug,further increasing the probability of detonator failure.Measures such as selecting injection-molded plugs made by high-quality PVC material,reducing the clamp diameter,and improving the crimping process,can reduce the impact of ambient temperature on the water resistance of electronic detonators.

Abstract:When explosives explode in the air free field,air shock wave will propagate outward,causing damage and destruction to the target.The destruction effect of shock wave on the target mainly depends on the characteristic parameters of the shock wave positive pressure phase region.Domestic and international scholars have conducted a lot of theoretical analyses,numerical simulations,and experimental researches on explosion shock wave parameters,achieving numerous research outcomes.This paper reviews the empirical formulas for characteristic parameters of shock waves in the positive pressure phase region,including peak over pressure,specific impulse,positive pressure duration,and shock wave arrival time.These formulas are compared and analyzed against numerical simulation and experimental data,to get empirical formulas that can more accurately describe explosion shock wave parameters.It provides a reference for the research on the assessment of explosive explosion shock wave parameters and explosion protection.