Research on Engineering Blasting Accident Analysis and Preventive Countermeasures based on AHP-Multilevel Fuzzy Comprehensive Assessment Methods
WANG Ai-hua
Engineering blasting serves as a critical technology in mineral extraction and infrastructure development, yet carries inherent operational safety risks. To establish a scientific and systematic safety risk assessment framework with targeted preventive measures, this study develops a risk evaluation model that addresses uncertainty and ambiguity in the assessment process. Based on an analysis of 90 engineering blasting accidents in China (2014—2024), a causal index system spanning four dimensions was constructed: human, machine (object), environment, and management. Statistical analysis indicates human unsafe behavior' (particularly illegal operation) as the primary direct cause. At the same time, management defects' (particularly inadequate safety training, unimplemented safety protocols, and disorganized site management) constitute fundamental systemic causes. To address quantification challenges in risk evaluation, fuzzy mathematical theory and the analytic hierarchy process (AHP) were integrated to determine indicator weights, thereby establishing an AHP-based multilevel fuzzy comprehensive evaluation model. Case validation confirms the model's effectiveness in assessing overall blasting safety status and identifying risk levels across causal dimensions, enabling key risk factor identification. Based on model outputs and a detailed accident analysis, comprehensive preventive countermeasures against engineering blasting accidents were systematically proposed across four domains: technology, management, personnel, and emergency response. The findings demonstrate the model's scientific utility for dynamic risk control, suggesting countermeasures such as enhanced safety training, improved equipment maintenance, optimized environmental controls, and strengthened safety accountability systems. This study provides both a theoretical foundation and practical guidance for mitigating engineering blasting risks.Engineering blasting serves as a critical technology in mineral extraction and infrastructure development, yet carries inherent operational safety risks. To establish a scientific and systematic safety risk assessment framework with targeted preventive measures, this study develops a risk evaluation model that addresses uncertainty and ambiguity in the assessment process. Based on an analysis of 90 engineering blasting accidents in China (2014—2024), a causal index system spanning four dimensions was constructed: human, machine (object), environment, and management. Statistical analysis indicates human unsafe behavior' (particularly illegal operation) as the primary direct cause. At the same time, management defects' (particularly inadequate safety training, unimplemented safety protocols, and disorganized site management) constitute fundamental systemic causes. To address quantification challenges in risk evaluation, fuzzy mathematical theory and the analytic hierarchy process (AHP) were integrated to determine indicator weights, thereby establishing an AHP-based multilevel fuzzy comprehensive evaluation model. Case validation confirms the model's effectiveness in assessing overall blasting safety status and identifying risk levels across causal dimensions, enabling key risk factor identification. Based on model outputs and a detailed accident analysis, comprehensive preventive countermeasures against engineering blasting accidents were systematically proposed across four domains: technology, management, personnel, and emergency response. The findings demonstrate the model's scientific utility for dynamic risk control, suggesting countermeasures such as enhanced safety training, improved equipment maintenance, optimized environmental controls, and strengthened safety accountability systems. This study provides both a theoretical foundation and practical guidance for mitigating engineering blasting risks.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 235 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.025
Effects of Fine Water Mist on Flame Propagation Characteristics and Quenching Behavior in Methane Explosions
XIA Jing-yi, DENG Yu-xuan, LI Jia-shuang, LU Chang, and CHEN Shuo
To investigate the influence of fine water mist on gas explosion propagation in pipelines under adverse pressure conditions, an experimental platform was designed and built to explore the effect of fine water mist on the explosion characteristics of 9.5% CH4/Air premixed gas. The experimental study employed a transparent acrylic pipeline system to simulate underground coal mine tunnel structures. It systematically investigated the influence of fine water mist on explosion overpressure, flame propagation velocity, and combustion characteristics. The experimental results demonstrate that fine water mist can significantly attenuate explosion overpressure and intensity while inducing flame quenching and backflow phenomena. Through thermal absorption in the combustion zone, the water mist reduces internal tube pressure below atmospheric levels, creating a negative-pressure zone where airflow reversal exceeds the flame-propagation velocity, effectively suppressing flame advancement. Experimental results reveal that fine water mist exhibits strong suppression of low-velocity flame propagation but is less effective against high-velocity flames. Furthermore, in extended pipeline systems with multiple nozzles, the spatial arrangement and configuration of the nozzles critically influence both the frequency and duration of flame backflow. Fine water mist demonstrates significant suppression of gas explosion propagation through combined physical and chemical mechanisms, particularly during low-velocity flame propagation phases, making it a viable safety technology for coal mine explosion mitigation.To investigate the influence of fine water mist on gas explosion propagation in pipelines under adverse pressure conditions, an experimental platform was designed and built to explore the effect of fine water mist on the explosion characteristics of 9.5% CH4/Air premixed gas. The experimental study employed a transparent acrylic pipeline system to simulate underground coal mine tunnel structures. It systematically investigated the influence of fine water mist on explosion overpressure, flame propagation velocity, and combustion characteristics. The experimental results demonstrate that fine water mist can significantly attenuate explosion overpressure and intensity while inducing flame quenching and backflow phenomena. Through thermal absorption in the combustion zone, the water mist reduces internal tube pressure below atmospheric levels, creating a negative-pressure zone where airflow reversal exceeds the flame-propagation velocity, effectively suppressing flame advancement. Experimental results reveal that fine water mist exhibits strong suppression of low-velocity flame propagation but is less effective against high-velocity flames. Furthermore, in extended pipeline systems with multiple nozzles, the spatial arrangement and configuration of the nozzles critically influence both the frequency and duration of flame backflow. Fine water mist demonstrates significant suppression of gas explosion propagation through combined physical and chemical mechanisms, particularly during low-velocity flame propagation phases, making it a viable safety technology for coal mine explosion mitigation.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 225 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.024
Research on Peak Particle Velocity Prediction of Blasting Vibration based on Particle Swarm Optimization and Ensemble Learning
XU Chen, LI Qi-le, QIU Lang, WANG Chao, REN Gao-feng, ZHAO Liang, LIU Chi, and MU Peng-yu
To accurately predict blasting vibration peak particle velocity and mitigate vibration hazards, this study develops a Stacking ensemble learning model (PSO-Stacking) optimized via a particle swarm optimization (PSO) algorithm, using field data from engineering applications. Five critical parameters were identified as key influencing factors: blast center distance, single-stage drug volume, borehole spacing, stemming length, and hole depth. The model's predictive performance was substantially enhanced through PSO-based hyperparameter optimization, including the number of depth levels of random forest (RF) decision trees, the support vector regression (SVR) penalty coefficient, and the number of trees in the gradient boosting decision tree (GBDT) within the Stacking framework. Experimental results demonstrate that the PSO-Stacking model achieves 85.54% accuracy (AR), with the mean square error (MSE), root mean square error (RMSE), and coefficient of determination (R2) being 2.39, 1.54, and 0.7361, respectively, which shows better prediction performance and generalization ability than the six models, such as PSO-RF, BPNN, and AdaBoost.To accurately predict blasting vibration peak particle velocity and mitigate vibration hazards, this study develops a Stacking ensemble learning model (PSO-Stacking) optimized via a particle swarm optimization (PSO) algorithm, using field data from engineering applications. Five critical parameters were identified as key influencing factors: blast center distance, single-stage drug volume, borehole spacing, stemming length, and hole depth. The model's predictive performance was substantially enhanced through PSO-based hyperparameter optimization, including the number of depth levels of random forest (RF) decision trees, the support vector regression (SVR) penalty coefficient, and the number of trees in the gradient boosting decision tree (GBDT) within the Stacking framework. Experimental results demonstrate that the PSO-Stacking model achieves 85.54% accuracy (AR), with the mean square error (MSE), root mean square error (RMSE), and coefficient of determination (R2) being 2.39, 1.54, and 0.7361, respectively, which shows better prediction performance and generalization ability than the six models, such as PSO-RF, BPNN, and AdaBoost.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 213 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.023
Investigation of Blasting Vibration Propagation Characteristics in Stopes Using Upward Horizontal Cut and Fill Mining Method
YIN Dong-sheng, YANG Yu-min, XIAO Ze-yu, LYU Guo-peng, and ZHENG Xu
Understanding blast vibration propagation mechanisms in underground stopes with complex roadway configurations is crucial for ensuring safe blasting operations. This study presents a comparative analysis of blast-induced vibration characteristics in the deep mining operations at the Tonglushan Copper-Iron Mine. Through systematic field blasting tests, the vibration velocity, dominant frequency, and blasting energy were measured at monitoring points in the upper-level and current-level drilling roadways. To enhance the reliability and completeness of vibration data, five supplementary field blasting tests were systematically conducted in coordination with the operational schedule of Tonglushan Copper-Iron Mine's production activities. Vibration monitoring stations were strategically established at multiple positions within both the current-level and upper-level drilling roadways to capture comprehensive blast-induced dynamic responses. The study employed the Sadovsky formula to systematically characterize blast vibration propagation patterns in both upper-level and current-level drilling roadways of the underground stope. This analytical approach established critical relationships for vibration attenuation that directly informed the engineering design of safe blasting parameters for site operations. Key findings reveal that, at comparable blast-center distances, high-frequency components exhibit significantly greater attenuation than low-frequency signals when interacting with roadway structures and dissipate more energy during stress wave propagation through rock mass matrices. Furthermore, the segmental maximum instantaneous energy measurements show comparable values between the upper-level drilling roadway. However, the upper-level drilling roadway exhibits significantly higher cumulative blasting energy than the current-level drilling roadway, attributed to longer instantaneous energy durations in each segment. Additionally, the upper-level drilling roadway shows consistently lower triaxial peak vibration velocities and lower attenuation rates than the upper-level roadway.Understanding blast vibration propagation mechanisms in underground stopes with complex roadway configurations is crucial for ensuring safe blasting operations. This study presents a comparative analysis of blast-induced vibration characteristics in the deep mining operations at the Tonglushan Copper-Iron Mine. Through systematic field blasting tests, the vibration velocity, dominant frequency, and blasting energy were measured at monitoring points in the upper-level and current-level drilling roadways. To enhance the reliability and completeness of vibration data, five supplementary field blasting tests were systematically conducted in coordination with the operational schedule of Tonglushan Copper-Iron Mine's production activities. Vibration monitoring stations were strategically established at multiple positions within both the current-level and upper-level drilling roadways to capture comprehensive blast-induced dynamic responses. The study employed the Sadovsky formula to systematically characterize blast vibration propagation patterns in both upper-level and current-level drilling roadways of the underground stope. This analytical approach established critical relationships for vibration attenuation that directly informed the engineering design of safe blasting parameters for site operations. Key findings reveal that, at comparable blast-center distances, high-frequency components exhibit significantly greater attenuation than low-frequency signals when interacting with roadway structures and dissipate more energy during stress wave propagation through rock mass matrices. Furthermore, the segmental maximum instantaneous energy measurements show comparable values between the upper-level drilling roadway. However, the upper-level drilling roadway exhibits significantly higher cumulative blasting energy than the current-level drilling roadway, attributed to longer instantaneous energy durations in each segment. Additionally, the upper-level drilling roadway shows consistently lower triaxial peak vibration velocities and lower attenuation rates than the upper-level roadway.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 203 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.022
Blasting Network Optimization and Application for Urban Subway Drift in Complex Environments
TIAN Cheng-lin, ZHAO Zi-long, LI Zhong-hui, ZHANG Wen-xi, ZHOU Yue-long, WU Xian-ming, ZENG Wang, and SUN Yong
The Jiangshuiquan Road Station tunnel construction along Jinan Metro Line 4 is located in a highly urbanized area with building proximity constraints, featuring a critical minimum clearance of 3.58 m between the underground excavation zone and adjacent pier foundations. This study consequently established a controlled test section within the subway tunnel project, characterized by lower blasting risk potential, to conduct systematic comparative analyses of three distinct blast initiation network configurations: S-patterned, co-directional, and bilateral-oriented vaults. Under controlled blasting conditions with 50 ms inter-row and 5ms inter-hole, comprehensive monitoring of pavement vibration velocities and waveform characteristics was carried out to evaluate vibration differentials across distinct initiation networks systematically. Concurrent quantitative analysis of rock fragmentation effects revealed that, while maintaining identical blasting parameters, the S-patterned detonation network generated the highest peak particle velocity of 0.87 cm/s, followed by co-directional detonation (0.55 cm/s), with the lowest on both sides (0.41 cm/s). Comparative analysis reveals that co-directional detonation achieves a 37% reduction in peak vibration velocity compared to S-patterned detonation. In comparison, the bilateral crown-oriented detonation demonstrates optimal vibration attenuation, achieving approximately 52% peak reduction. Post-blast fragmentation analysis further indicates that the bilateral-to-center detonation method yields the lowest oversized fragment rate (<25%) and concurrently the highest fine particle proportion, thereby exhibiting superior overall fragmentation quality. Finally, the bilateral crown-oriented detonation network was implemented in the highest-risk blasting zone adjacent to pier foundations to validate these findings. This study establishes a methodological framework for optimizing initiation networks and controlling blast-induced vibrations in urban subway tunnel construction within a complex environment.The Jiangshuiquan Road Station tunnel construction along Jinan Metro Line 4 is located in a highly urbanized area with building proximity constraints, featuring a critical minimum clearance of 3.58 m between the underground excavation zone and adjacent pier foundations. This study consequently established a controlled test section within the subway tunnel project, characterized by lower blasting risk potential, to conduct systematic comparative analyses of three distinct blast initiation network configurations: S-patterned, co-directional, and bilateral-oriented vaults. Under controlled blasting conditions with 50 ms inter-row and 5ms inter-hole, comprehensive monitoring of pavement vibration velocities and waveform characteristics was carried out to evaluate vibration differentials across distinct initiation networks systematically. Concurrent quantitative analysis of rock fragmentation effects revealed that, while maintaining identical blasting parameters, the S-patterned detonation network generated the highest peak particle velocity of 0.87 cm/s, followed by co-directional detonation (0.55 cm/s), with the lowest on both sides (0.41 cm/s). Comparative analysis reveals that co-directional detonation achieves a 37% reduction in peak vibration velocity compared to S-patterned detonation. In comparison, the bilateral crown-oriented detonation demonstrates optimal vibration attenuation, achieving approximately 52% peak reduction. Post-blast fragmentation analysis further indicates that the bilateral-to-center detonation method yields the lowest oversized fragment rate (<25%) and concurrently the highest fine particle proportion, thereby exhibiting superior overall fragmentation quality. Finally, the bilateral crown-oriented detonation network was implemented in the highest-risk blasting zone adjacent to pier foundations to validate these findings. This study establishes a methodological framework for optimizing initiation networks and controlling blast-induced vibrations in urban subway tunnel construction within a complex environment.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 190 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.021
Study on Method and Mechanism for Controlled Boundary Blasting Using Underwater Shaped Charge
WANG Jie-yun, WANG Zhe, XU Xin, JIANG Nan, and DING Jian
To achieve precise excavation boundary control and promote planar cracks propagation in underwater blasting operations, this study systematically investigates fracture initiation mechanisms through the deployment of multi-point bidirectional shaped charges submerged in aqueous environments. Based on the unique energy transmission dynamics of underwater explosions, compact-volume shaped charges were engineered with forward-positioned air cavities adjacent to the liners, optimizing jet formation efficiency and directional fracture control. The actuation sequence and planar fracturing mechanism of the underwater shaped charge were comprehensively analyzed through integrated 2D and 3D numerical simulations and concrete splitting experiments. The results demonstrate that the designed actuation sequence proceeds through distinct phases: blast shockwave propagation, head shockwave formation, shaped jet generation, hydraulic wedge action, and bubble pulsation effects. The synergistic interaction of these mechanisms establishes an optimized chronological sequence that, when coupled with pre-cut borehole grooves, induces a tensile stress concentration zone along the predetermined fracture plane, facilitating preferential crack initiation and controlled propagation. Field validation tests successfully generated planar fractures in concrete targets using a remarkably low linear charge density (39 g/m), with fracture patterns exhibiting exceptional alignment with the designed splitting plane and strong correlation with numerical simulation. These findings confirm both the operational feasibility of the charge configuration and the predictive accuracy of the computational model. The developed methodology offers significant practical value for boundary-controlled blasting applications in underwater environments and in terrestrial settings requiring stringent blast-impact mitigation.To achieve precise excavation boundary control and promote planar cracks propagation in underwater blasting operations, this study systematically investigates fracture initiation mechanisms through the deployment of multi-point bidirectional shaped charges submerged in aqueous environments. Based on the unique energy transmission dynamics of underwater explosions, compact-volume shaped charges were engineered with forward-positioned air cavities adjacent to the liners, optimizing jet formation efficiency and directional fracture control. The actuation sequence and planar fracturing mechanism of the underwater shaped charge were comprehensively analyzed through integrated 2D and 3D numerical simulations and concrete splitting experiments. The results demonstrate that the designed actuation sequence proceeds through distinct phases: blast shockwave propagation, head shockwave formation, shaped jet generation, hydraulic wedge action, and bubble pulsation effects. The synergistic interaction of these mechanisms establishes an optimized chronological sequence that, when coupled with pre-cut borehole grooves, induces a tensile stress concentration zone along the predetermined fracture plane, facilitating preferential crack initiation and controlled propagation. Field validation tests successfully generated planar fractures in concrete targets using a remarkably low linear charge density (39 g/m), with fracture patterns exhibiting exceptional alignment with the designed splitting plane and strong correlation with numerical simulation. These findings confirm both the operational feasibility of the charge configuration and the predictive accuracy of the computational model. The developed methodology offers significant practical value for boundary-controlled blasting applications in underwater environments and in terrestrial settings requiring stringent blast-impact mitigation.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 178 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.020
Research on Controlled Blasting Construction Technology in Extreme Temperature Environments
DU ZHONG-long, WANG Gao-long and LI SHU-qiang
This study addresses the extreme geological conditions, including high-temperature spontaneous combustion, steep, high slopes, and a complex network of abandoned workings in the fire-affected southern wing of Wuhai Energy's Lutian Coal Mine. Focusing on non-ambient temperature environments, the research examines construction management strategies and technical solutions for geological hazard control using thermo-mechanical coupling theory. Field experiments, numerical modeling, and theoretical studies were combined to develop a “temperature-zoning/thermo-mechanical coupling/differential-design” blasting method. The implemented solution features an integrated protection package of “water injection for cooling+gel insulation+PVC-sleeve isolation” together with digital electronic detonator precision initiation. Key findings include the characterization of the effects of temperature on rock mass mechanics and blasting dynamics, along with the development of a temperature-dependent dynamic constitutive model for rock masses. The proposed systematic approach integrates temperature zoning analysis, coupled thermo-mechanical evaluation, customized design, and coordinated control measures, establishing a multi-hazard mitigation system utilizing digital electronic detonators. Practical applications demonstrated exceptional safety performance with blast vibrations controlled below 0.38 cm·s-1, flyrock limited to under 50 m, and complete success in high-temperature hole cooling, achieving the safety objectives of “zero injuries, zero accidents, and zero environmental contamination”. These results offer valuable theoretical foundations and practical methodologies for managing geological risks in mining operations under extreme temperature conditions.This study addresses the extreme geological conditions, including high-temperature spontaneous combustion, steep, high slopes, and a complex network of abandoned workings in the fire-affected southern wing of Wuhai Energy's Lutian Coal Mine. Focusing on non-ambient temperature environments, the research examines construction management strategies and technical solutions for geological hazard control using thermo-mechanical coupling theory. Field experiments, numerical modeling, and theoretical studies were combined to develop a “temperature-zoning/thermo-mechanical coupling/differential-design” blasting method. The implemented solution features an integrated protection package of “water injection for cooling+gel insulation+PVC-sleeve isolation” together with digital electronic detonator precision initiation. Key findings include the characterization of the effects of temperature on rock mass mechanics and blasting dynamics, along with the development of a temperature-dependent dynamic constitutive model for rock masses. The proposed systematic approach integrates temperature zoning analysis, coupled thermo-mechanical evaluation, customized design, and coordinated control measures, establishing a multi-hazard mitigation system utilizing digital electronic detonators. Practical applications demonstrated exceptional safety performance with blast vibrations controlled below 0.38 cm·s-1, flyrock limited to under 50 m, and complete success in high-temperature hole cooling, achieving the safety objectives of “zero injuries, zero accidents, and zero environmental contamination”. These results offer valuable theoretical foundations and practical methodologies for managing geological risks in mining operations under extreme temperature conditions.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 171 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.019
Underwater Demolition Blasting for Old KOT Oil Terminal Berthing Piers at Mombasa Port, Kenya
LI Quan and JIANG Ming-ming
During the construction of Berth 19B project at Mombasa Port in Kenya, complete demolition of all existing structures at the old KOT oil terminal was required as part of the construction process. The demolition of the old terminal initially utilized mechanical methods, yet three berthing piers remained intact. Consequently, controlled blasting was selected for their removal. This study examined the technical specifications of the piers, their structural engineering features, the operational characteristics of locally procured India blasting equipment, and the implementation strategy for single-phase explosive demolition. The demolition plan calculated explosive unit consumption specifically tailored for the unique structural configuration of the berthing piers, followed by trial blasting operations for parameter optimization. The plan incorporated a dual-hole sequential initiation network using high-precision non-electric detonators sourced from India, guaranteeing compliance with all regulatory limits for both ground vibration and underwater shock waves despite the single-blast explosive quantity approaching 6 metric tons. The paper also detailed the construction and strategic deployment of an open-water bubble curtain system along the wharf's operational area.During the construction of Berth 19B project at Mombasa Port in Kenya, complete demolition of all existing structures at the old KOT oil terminal was required as part of the construction process. The demolition of the old terminal initially utilized mechanical methods, yet three berthing piers remained intact. Consequently, controlled blasting was selected for their removal. This study examined the technical specifications of the piers, their structural engineering features, the operational characteristics of locally procured India blasting equipment, and the implementation strategy for single-phase explosive demolition. The demolition plan calculated explosive unit consumption specifically tailored for the unique structural configuration of the berthing piers, followed by trial blasting operations for parameter optimization. The plan incorporated a dual-hole sequential initiation network using high-precision non-electric detonators sourced from India, guaranteeing compliance with all regulatory limits for both ground vibration and underwater shock waves despite the single-blast explosive quantity approaching 6 metric tons. The paper also detailed the construction and strategic deployment of an open-water bubble curtain system along the wharf's operational area.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 166 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.018
Study on Dynamic Load Adjustment Mechanism of Frame-Structure Buildings under Mechanical Demolition Conditions
LI Kang, HOU Yong-heng, DONG Si-ling, HUANG Xiao-wu, and YAO Ying-kang
Focusing on the issue of dynamic load redistribution during mechanical demolition of high-rise buildings, this study takes the mechanical demolition of an 8-story frame structure building in Wuhan City as the engineering background. First, a field test was conducted on the cutting and removal of a single column, using dynamic strain testing techniques to measure real-time load transfer characteristics in the overlying beam. Subsequently, the LS-DYNA was used to simulate the single-column mechanical demolition field test scenario, and the numerical model's reliability was verified by comparing simulation results with field-measured data. Finally, the established numerical model was used to simulate mechanical demolition conditions, analyzing internal force variations to investigate dynamic load redistribution mechanisms and structural failure characteristics. The results indicate that during single-column removal, tensile strain of 102 magnitude occurred at the bottom of the near-end beam. In contrast, the far end developed compressive strain ranging from 101 to 102. The structural system redistributed internal forces through beam bending. During sequential column demolition, individual column failures generated transient tensile stresses in neighboring columns. Variations in demolition sequence and time intervals substantially altered stress redistribution pathways across structural components, leading to non-uniform force distribution. Additionally, stress concentration and structural deformation exhibited certain delays during sequential demolition, which may induce directional deviations in collapse patterns. The findings of this study can provide valuable references for the design of mechanical demolition of high-rise buildings and the analysis of dynamic load adjustment in structures.Focusing on the issue of dynamic load redistribution during mechanical demolition of high-rise buildings, this study takes the mechanical demolition of an 8-story frame structure building in Wuhan City as the engineering background. First, a field test was conducted on the cutting and removal of a single column, using dynamic strain testing techniques to measure real-time load transfer characteristics in the overlying beam. Subsequently, the LS-DYNA was used to simulate the single-column mechanical demolition field test scenario, and the numerical model's reliability was verified by comparing simulation results with field-measured data. Finally, the established numerical model was used to simulate mechanical demolition conditions, analyzing internal force variations to investigate dynamic load redistribution mechanisms and structural failure characteristics. The results indicate that during single-column removal, tensile strain of 102 magnitude occurred at the bottom of the near-end beam. In contrast, the far end developed compressive strain ranging from 101 to 102. The structural system redistributed internal forces through beam bending. During sequential column demolition, individual column failures generated transient tensile stresses in neighboring columns. Variations in demolition sequence and time intervals substantially altered stress redistribution pathways across structural components, leading to non-uniform force distribution. Additionally, stress concentration and structural deformation exhibited certain delays during sequential demolition, which may induce directional deviations in collapse patterns. The findings of this study can provide valuable references for the design of mechanical demolition of high-rise buildings and the analysis of dynamic load adjustment in structures.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 156 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.017
Controlled Blasting Demolition of Two Chimneys with Opposite Staggered Collapse in Complex Environment
LI Jie, WANG Yuan-yuan, ZHANG Yi-ping, and LIU Deng-ke
To comply with national environmental regulations, controlled blasting was used to demolish two chimneys at a decommissioned coking plant in Bijie City. The twin chimneys exhibited identical material composition and dimensional specifications: each was a reinforced concrete structure with preserved external shells, incorporating refractory brick linings. Both structures measured 85 meters in height, with identical geometric parameters: a 7-meter outer diameter (21.98-meter circumference) at the base, featuring 36-cm-thick outer walls, 24-cm-thick refractory linings, and a 4-cm insulating air gap between concentric layers. Situated in an urban setting with complex surroundings, the chimneys were proximate to protected infrastructure, including industrial buildings, residential areas, and roadways (minimum clearance: 60 meters). This required stringent mitigation of blast-induced hazards, particularly ground vibration and flyrock. Given that simultaneous detonation would produce excessive vibration, a sequential millisecond-delay blasting technique with 110 ms inter-chimney delay was implemented. To minimize collapse-induced ground vibrations, four sand-soil cushion berms were strategically placed in the anticipated impact zones. Flyrock prevention was ensured by double-layer rubber-mesh reinforcement over the blast-cut sections. Computational analysis verified compliance with all safety standards for blast-induced hazards, including vibration and flyrock. Field observations confirmed the chimneys achieved controlled diagonal collapse in opposite directions as planned. Vibration monitoring at the closest protected structure registered 0.66 cm/s, well below the prescribed safety limit, while flyrock was effectively contained within designated boundaries. This successful demolition offers key technical benchmarks for similar engineering projects.To comply with national environmental regulations, controlled blasting was used to demolish two chimneys at a decommissioned coking plant in Bijie City. The twin chimneys exhibited identical material composition and dimensional specifications: each was a reinforced concrete structure with preserved external shells, incorporating refractory brick linings. Both structures measured 85 meters in height, with identical geometric parameters: a 7-meter outer diameter (21.98-meter circumference) at the base, featuring 36-cm-thick outer walls, 24-cm-thick refractory linings, and a 4-cm insulating air gap between concentric layers. Situated in an urban setting with complex surroundings, the chimneys were proximate to protected infrastructure, including industrial buildings, residential areas, and roadways (minimum clearance: 60 meters). This required stringent mitigation of blast-induced hazards, particularly ground vibration and flyrock. Given that simultaneous detonation would produce excessive vibration, a sequential millisecond-delay blasting technique with 110 ms inter-chimney delay was implemented. To minimize collapse-induced ground vibrations, four sand-soil cushion berms were strategically placed in the anticipated impact zones. Flyrock prevention was ensured by double-layer rubber-mesh reinforcement over the blast-cut sections. Computational analysis verified compliance with all safety standards for blast-induced hazards, including vibration and flyrock. Field observations confirmed the chimneys achieved controlled diagonal collapse in opposite directions as planned. Vibration monitoring at the closest protected structure registered 0.66 cm/s, well below the prescribed safety limit, while flyrock was effectively contained within designated boundaries. This successful demolition offers key technical benchmarks for similar engineering projects.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 148 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.016
Damage Characteristics of Reinforced Concrete Components in Near-field of Blast Holes under Drilling and Blasting Conditions
YAO Ying-kang, KANG Yi-ze, ZHANG Qiang, ZHANG Cheng, and WANG Wei
Revealing the failure mechanisms of reinforced concrete beams and columns under drilling and blasting conditions is essential for achieving precise blasting demolition design and accurate assessment of blasting effects. Based on an actual deep foundation pit support beam blasting demolition project, this research investigated the dynamic strain characteristics of the hole wall, near-field zone, and the mid-to-far zones under single-hole blasting conditions through field blasting tests and strain measurements. Through explosion dynamics theory, the study calculated borehole wall pressure, damage factors, and damage zoning characteristics. Results demonstrate that under combined blast stress waves and quasi-static gas effects, reinforced concrete support beams exhibit first compression and then pull' strain characteristics in borehole walls and near-field concrete, with measured strain curves closely aligning with numerical simulation results at both tensile and compressive peaks. The damage distribution in reinforced concrete beams subjected to blasting exhibited a nonlinear attenuation pattern, characterized by rapid decay in the near-field region and gradual reduction to zero in the far-field region. Both numerical simulations and theoretical calculations demonstrated good agreement in the extent of the crushing and fracture zones, with approximately 10% absolute deviation between the two methods. The theoretical and numerical models developed in this study effectively analyze blast-induced damage zoning, with findings offering valuable references for assessing damage characteristics and affected areas in reinforced concrete components during demolition blasting.Revealing the failure mechanisms of reinforced concrete beams and columns under drilling and blasting conditions is essential for achieving precise blasting demolition design and accurate assessment of blasting effects. Based on an actual deep foundation pit support beam blasting demolition project, this research investigated the dynamic strain characteristics of the hole wall, near-field zone, and the mid-to-far zones under single-hole blasting conditions through field blasting tests and strain measurements. Through explosion dynamics theory, the study calculated borehole wall pressure, damage factors, and damage zoning characteristics. Results demonstrate that under combined blast stress waves and quasi-static gas effects, reinforced concrete support beams exhibit first compression and then pull' strain characteristics in borehole walls and near-field concrete, with measured strain curves closely aligning with numerical simulation results at both tensile and compressive peaks. The damage distribution in reinforced concrete beams subjected to blasting exhibited a nonlinear attenuation pattern, characterized by rapid decay in the near-field region and gradual reduction to zero in the far-field region. Both numerical simulations and theoretical calculations demonstrated good agreement in the extent of the crushing and fracture zones, with approximately 10% absolute deviation between the two methods. The theoretical and numerical models developed in this study effectively analyze blast-induced damage zoning, with findings offering valuable references for assessing damage characteristics and affected areas in reinforced concrete components during demolition blasting.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 138 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.015
Study on Controlled Blasting Techniques for Hazard Mitigation of Unstable Rock Masses on High and Steep Slopes under Complex Environmental Conditions
ZHANG Jian, YAO Ning, LI Yong, AN Rong-jie, and LU Shi-jia
Rock collapse, as a typical geological hazard, exhibits sudden occurrence and high destructive potential, severely threatening lives and infrastructure in adjacent areas. Currently, control blasting has become a prevalent mitigation measure for unstable rock masses susceptible to collapse. This study investigates the unstable rock mass on the back hill of Longgui Village, Shanglin County, Nanning City, Guangxi, utilizing a high-density drilling configuration with a hole network parameter of 0.35 m×0.40 m, involving over 350 blast holes. The blasted debris fragmentation size was precisely controlled with a maximum volume of 0.0429 m3. By applying air-deck charging in combination with detonating cord series connection technology, the explosive pressure duration on borehole walls was prolonged, generating a quasi-static pressure effect that successfully mitigated impact crushing and minimized long-distance flyrock hazards. A total explosive charge of 462 kg was strategically divided into six segments with sequential outward-to-inward initiation using 20 ms inter-segment delays, maintaining a maximum charge of 79.2 kg per delay interval. This design promoted rock-to-rock collisions for secondary fragmentation, resulting in enhanced size reduction. The blast successfully generated a controlled "rock debris waterfall" collapse pattern, completing the hazard mitigation operation. This project establishes a technically viable approach for the removal of overhanging rock masses near critical infrastructure, including mountain transportation corridors and civilian structures.Rock collapse, as a typical geological hazard, exhibits sudden occurrence and high destructive potential, severely threatening lives and infrastructure in adjacent areas. Currently, control blasting has become a prevalent mitigation measure for unstable rock masses susceptible to collapse. This study investigates the unstable rock mass on the back hill of Longgui Village, Shanglin County, Nanning City, Guangxi, utilizing a high-density drilling configuration with a hole network parameter of 0.35 m×0.40 m, involving over 350 blast holes. The blasted debris fragmentation size was precisely controlled with a maximum volume of 0.0429 m3. By applying air-deck charging in combination with detonating cord series connection technology, the explosive pressure duration on borehole walls was prolonged, generating a quasi-static pressure effect that successfully mitigated impact crushing and minimized long-distance flyrock hazards. A total explosive charge of 462 kg was strategically divided into six segments with sequential outward-to-inward initiation using 20 ms inter-segment delays, maintaining a maximum charge of 79.2 kg per delay interval. This design promoted rock-to-rock collisions for secondary fragmentation, resulting in enhanced size reduction. The blast successfully generated a controlled "rock debris waterfall" collapse pattern, completing the hazard mitigation operation. This project establishes a technically viable approach for the removal of overhanging rock masses near critical infrastructure, including mountain transportation corridors and civilian structures.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 130 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.014
Improvement of Blasting Performance for Honeycomb-structured Copper-cobalt Oxide Ore in Open-pit Mines
DU Jun, WANG Ming-wei, ZHENG Jun-wei, JIN Hong-yang, FENG Kai, LIU Zeng-hui, and HA Shou-bin
Open-pit mining areas, particularly those containing copper-cobalt oxide ores, frequently feature honeycomb-structured ore bodies with extensive geological discontinuities, including joints and cavities, creating substantial difficulties during stripping operations. This phenomenon is especially pronounced during blasting operations, manifesting as low borehole formation rates, elevated high boulder yield, inadequate fragmentation, and hard toe. All of which significantly compromise subsequent excavation and loading efficiency while simultaneously introducing operational safety risks. To optimize blasting effects in honeycomb-structured copper-cobalt oxide ores while maintaining economic feasibility, three key improvements were implemented: enhancing drilling success through reduced depth/diameter, increasing charge height via anti-static PVC pipe confinement and cartridge hoisting, and parameter adjustments to satisfy subsequent construction requirements. The results demonstrate that this approach substantially enhances post-blasting performance metrics, including boulder yield, hard toe occurrence, and fragmentation quality, effectively satisfying subsequent excavation and haulage requirements while optimizing stripping operations for the following mining cycle.Open-pit mining areas, particularly those containing copper-cobalt oxide ores, frequently feature honeycomb-structured ore bodies with extensive geological discontinuities, including joints and cavities, creating substantial difficulties during stripping operations. This phenomenon is especially pronounced during blasting operations, manifesting as low borehole formation rates, elevated high boulder yield, inadequate fragmentation, and hard toe. All of which significantly compromise subsequent excavation and loading efficiency while simultaneously introducing operational safety risks. To optimize blasting effects in honeycomb-structured copper-cobalt oxide ores while maintaining economic feasibility, three key improvements were implemented: enhancing drilling success through reduced depth/diameter, increasing charge height via anti-static PVC pipe confinement and cartridge hoisting, and parameter adjustments to satisfy subsequent construction requirements. The results demonstrate that this approach substantially enhances post-blasting performance metrics, including boulder yield, hard toe occurrence, and fragmentation quality, effectively satisfying subsequent excavation and haulage requirements while optimizing stripping operations for the following mining cycle.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 123 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.013
Fragmentation Characteristics and Response Behavior of Loess Surrounding Rock under Blasting Operations
ZHANG Wen-jie, DENG Long-sheng, YU Bo, YANG Zhou, DU Zhong-dong, SONG Fang-shu, and ZOU Yu
In loess region blasting operations, the fragmentation and compaction effects on surrounding loess significantly influence both construction quality and blast design optimization. Field blasting experiments were conducted to examine these effects, utilizing digital image processing techniques to extract cavity surface crack and clod characteristics for loess fragmentation analysis. Concurrent measurements of blast cavity profiles and peripheral cracks were combined with laboratory testing to determine blast-affected soil zoning boundaries. Numerical modeling was implemented in LS-DYNA based on field data, with explosive length variations simulating different charge weights for loess blasting scenarios. The experimental results demonstrate that the post-blast loess exhibits five distinct elliptical zones: cavity zone, crushed zone, cracked zone, compacted zone, and elastic deformation zone. Within the crushed zone, the soil develops both wide fractures and short, thin cracks, predominantly interconnected through T- shaped nodal intersections. The resulting clods primarily display irregular quadrilateral morphology with complex geometries and extensive internal cracking networks. In contrast, the cracked zone predominantly develops elongated, narrow cracks interconnected through Y-shaped nodal intersections, exhibiting irregular pentagonal and hexagonal morphologies. Experimental analysis reveals a hyperbolic correlation between explosive weight and both the radial dimensions of the blast cavity and its influence range. In contrast, axial dimensions demonstrate linear proportionality to explosive mass.In loess region blasting operations, the fragmentation and compaction effects on surrounding loess significantly influence both construction quality and blast design optimization. Field blasting experiments were conducted to examine these effects, utilizing digital image processing techniques to extract cavity surface crack and clod characteristics for loess fragmentation analysis. Concurrent measurements of blast cavity profiles and peripheral cracks were combined with laboratory testing to determine blast-affected soil zoning boundaries. Numerical modeling was implemented in LS-DYNA based on field data, with explosive length variations simulating different charge weights for loess blasting scenarios. The experimental results demonstrate that the post-blast loess exhibits five distinct elliptical zones: cavity zone, crushed zone, cracked zone, compacted zone, and elastic deformation zone. Within the crushed zone, the soil develops both wide fractures and short, thin cracks, predominantly interconnected through T- shaped nodal intersections. The resulting clods primarily display irregular quadrilateral morphology with complex geometries and extensive internal cracking networks. In contrast, the cracked zone predominantly develops elongated, narrow cracks interconnected through Y-shaped nodal intersections, exhibiting irregular pentagonal and hexagonal morphologies. Experimental analysis reveals a hyperbolic correlation between explosive weight and both the radial dimensions of the blast cavity and its influence range. In contrast, axial dimensions demonstrate linear proportionality to explosive mass.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 109 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.012
Blasting Parameter Optimization of Underground Fan-shaped Medium-deep Holes based on Crater Test
XIONG Guo-xiong, LIU Tian-hao, YIN Dong-sheng, YANG Yu-min, and SHI De-hua
Under the deep geostress environment, ore-rock masses exhibit distinct mechanical properties and fragmentation characteristics that markedly differ from those observed in shallow deposits. To optimize the blasting parameters for fan-shaped medium-deep holes in the deep stope of Tonglushan Copper-Iron Mine, crater blasting tests were conducted at the 9428 stope of the -485 level, following a comprehensive analysis of the ore-rock mechanical properties at this depth. Optimized medium-length hole blasting parameters were systematically derived from a thorough analysis of crater morphology and specific explosive consumption characteristics, with subsequent industrial-scale trials confirming their technical validity and operational feasibility. The research findings demonstrate that the rock mass integrity coefficient of the skarn in the 9428 stope of the -485 level at Tonglushan Mine measures 0.39, classifying it as relatively fragmented according to the Standard for Engineering Classification of Rock Mass. Single-hole carter blasting tests revealed optimal parameters including: charge center burial depth (0.400 m), critical burial depth (0.898 m), strain energy coefficient (1.69 m/kg1/3), optimal burial depth ratio (0.445), optimal crater radius (0.461 m), and optimal crater volume (0.014 m). Subsequent double-hole and inclined bench crater tests determined an optimal hole spacing of 0.809 m and a minimum crater burden of 0.740 m. Applying blasting similarity theory to production-scale fan-shaped medium-deep holes (64 mm diameter), recommended parameters include: hole bottom spacing (1.3~1.6 m), hole mouth spacing (0.8~1.3 m), and row spacing (1.1~1.4 m).Under the deep geostress environment, ore-rock masses exhibit distinct mechanical properties and fragmentation characteristics that markedly differ from those observed in shallow deposits. To optimize the blasting parameters for fan-shaped medium-deep holes in the deep stope of Tonglushan Copper-Iron Mine, crater blasting tests were conducted at the 9428 stope of the -485 level, following a comprehensive analysis of the ore-rock mechanical properties at this depth. Optimized medium-length hole blasting parameters were systematically derived from a thorough analysis of crater morphology and specific explosive consumption characteristics, with subsequent industrial-scale trials confirming their technical validity and operational feasibility. The research findings demonstrate that the rock mass integrity coefficient of the skarn in the 9428 stope of the -485 level at Tonglushan Mine measures 0.39, classifying it as relatively fragmented according to the Standard for Engineering Classification of Rock Mass. Single-hole carter blasting tests revealed optimal parameters including: charge center burial depth (0.400 m), critical burial depth (0.898 m), strain energy coefficient (1.69 m/kg1/3), optimal burial depth ratio (0.445), optimal crater radius (0.461 m), and optimal crater volume (0.014 m). Subsequent double-hole and inclined bench crater tests determined an optimal hole spacing of 0.809 m and a minimum crater burden of 0.740 m. Applying blasting similarity theory to production-scale fan-shaped medium-deep holes (64 mm diameter), recommended parameters include: hole bottom spacing (1.3~1.6 m), hole mouth spacing (0.8~1.3 m), and row spacing (1.1~1.4 m).
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 99 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.011
Optimization of Charge Structure for Fan-hole Blasting in Underground Metal Mines
JIA Bei, XIONG Zan-min, GUO Lei, WANG Xiao, and QI Lu-lu
This study develops an optimized fan-hole charging configuration grounded in Livingston's crater theory to resolve the persistent challenges of collar zone over-fragmentation and toe region under-charging in conventional underground fan-hole blasting operations, which frequently generate undesirable oversized fragments. Numerical simulations employing LS-DYNA finite element software were performed to optimize fan-hole toe spacing. Through comprehensive analysis of rock damage zone distribution characteristics under both continuous and decked charging conditions, this study demonstrates the superior efficacy of decked charging in damage control, with field experimental results providing conclusive validation. Experimental results demonstrate that while the spaced charging configuration achieves comparable fragmentation effectiveness to continuous charging, it significantly reduces rock pulverization near boreholes, thereby minimizing powder mineralization. Implementation of the optimized charging structure yields stope blasting fragments with D20 and D80 sizes of 7.12 cm and 18.52 cm, respectively, with maximum block size rigorously constrained below 28.49 cm and minimal occurrence of sub-5 cm fines.This study develops an optimized fan-hole charging configuration grounded in Livingston's crater theory to resolve the persistent challenges of collar zone over-fragmentation and toe region under-charging in conventional underground fan-hole blasting operations, which frequently generate undesirable oversized fragments. Numerical simulations employing LS-DYNA finite element software were performed to optimize fan-hole toe spacing. Through comprehensive analysis of rock damage zone distribution characteristics under both continuous and decked charging conditions, this study demonstrates the superior efficacy of decked charging in damage control, with field experimental results providing conclusive validation. Experimental results demonstrate that while the spaced charging configuration achieves comparable fragmentation effectiveness to continuous charging, it significantly reduces rock pulverization near boreholes, thereby minimizing powder mineralization. Implementation of the optimized charging structure yields stope blasting fragments with D20 and D80 sizes of 7.12 cm and 18.52 cm, respectively, with maximum block size rigorously constrained below 28.49 cm and minimal occurrence of sub-5 cm fines.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 91 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.010
Numerical Simulation and Parameter Optimization of Fan-shaped Hole Blasting in Backfilled Sublevel Open Stoping
REN Shao-feng, WU Li-bo, WANG Da-long, PENG Shi-gang, LIU Kai, TAO Ming, and XU Yuan-quan
To address the issues of backfill damage and stope boundary irregularities caused by fan-shaped borehole blasting in sublevel open stoping with subsequent backfilling, this study focuses on the underground stope of Xinqiao Phosphate Mine as a case study. Numerical models were developed using LS-DYNA finite element software to comprehensively analyze the blasting performance of fan-shaped medium-deep holes under various operational conditions. Field-measured blasting contours of the stope were compared with numerical simulation results to evaluate the influence of different loading application methods on the blasting damage prediction accuracy. The simulations employed both experimentally recorded borehole wall pressure time-histories and a constitutive explosive material model coupled with the JWL equation, revealing that the measured load time-histories yielded more precise blasting effect representations. Building upon this foundation, the study systematically simulated fan-shaped blasting under one-step mining, two-step mining, and special stope conditions by examining two key variables: inter-sidewall distance and initiation delay time. Subsequent analysis focused on surrounding rock mass damage distribution patterns and blasting-induced vibration characteristics. Results indicate that in one-step mining scenarios, inter-sidewall distance exhibits limited impact on surrounding rock mass stability, while initiation delay time emerges as the predominant factor governing blast fragmentation efficiency. At a 0.3 m inter-sidewall distance, blasting damage primarily concentrated within the ore caving zone, achieving effective bulk fragmentation while substantially mitigating surrounding rock damage risks. In two-step mining scenarios, backfill stability demonstrates high sensitivity to toe burden distance, with damage risks markedly damage decreasing when exceeding 0.6 m. While sequential hole initiation enhanced fragmentation, it exacerbated backfill damage. Special stope conditions required asymmetric sidewall parameter design and optimized borehole arrangement to minimize backfill impacts. These findings culminate in an optimized fan-shaped blasting parameter system tailored for Xinqiao Phosphate Mine's A-orebody, delivering both theoretical frameworks and practical methodologies for backfill mining blasting operations.To address the issues of backfill damage and stope boundary irregularities caused by fan-shaped borehole blasting in sublevel open stoping with subsequent backfilling, this study focuses on the underground stope of Xinqiao Phosphate Mine as a case study. Numerical models were developed using LS-DYNA finite element software to comprehensively analyze the blasting performance of fan-shaped medium-deep holes under various operational conditions. Field-measured blasting contours of the stope were compared with numerical simulation results to evaluate the influence of different loading application methods on the blasting damage prediction accuracy. The simulations employed both experimentally recorded borehole wall pressure time-histories and a constitutive explosive material model coupled with the JWL equation, revealing that the measured load time-histories yielded more precise blasting effect representations. Building upon this foundation, the study systematically simulated fan-shaped blasting under one-step mining, two-step mining, and special stope conditions by examining two key variables: inter-sidewall distance and initiation delay time. Subsequent analysis focused on surrounding rock mass damage distribution patterns and blasting-induced vibration characteristics. Results indicate that in one-step mining scenarios, inter-sidewall distance exhibits limited impact on surrounding rock mass stability, while initiation delay time emerges as the predominant factor governing blast fragmentation efficiency. At a 0.3 m inter-sidewall distance, blasting damage primarily concentrated within the ore caving zone, achieving effective bulk fragmentation while substantially mitigating surrounding rock damage risks. In two-step mining scenarios, backfill stability demonstrates high sensitivity to toe burden distance, with damage risks markedly damage decreasing when exceeding 0.6 m. While sequential hole initiation enhanced fragmentation, it exacerbated backfill damage. Special stope conditions required asymmetric sidewall parameter design and optimized borehole arrangement to minimize backfill impacts. These findings culminate in an optimized fan-shaped blasting parameter system tailored for Xinqiao Phosphate Mine's A-orebody, delivering both theoretical frameworks and practical methodologies for backfill mining blasting operations.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 74 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.009
Influence of Rock Mass Fracture Distribution on Crack Formation Effectiveness and Control in Presplit Blasting
LI Yu-peng, GUO Li-an, HU Pan, HAO Bing-yuan, WANG Chen-long, ZHAO Ting-ting, and ZHANG Tao
During roof presplitting blasting for auxiliary air inlet and roof cutting gob-side entry retaining at Pingshu Coal Industry's 8213 working face, blast-induced fractures exhibit random propagation patterns and deviate from presplitting holes alignment due to the influence of pre-existing fractures. The presplit fractures exhibit discontinuous, rough, and serrated morphologies, resulting in rock masses interlocking that hinder effective separation along the presplitting hole plane and delay pressure relief. Consequently, the surrounding rock of the gob-side entry retaining maintains prolonged high-stress conditions, leading to significant deformations. To enhance roof-cutting effectiveness in fractured rock masses through presplitting blasting, this study employs the discrete element particle expansion method to numerically investigate how characteristic parameters of fracture distribution influence presplit fracturing outcomes. Furthermore, a multi-parameter coupling simulation system for rock mass presplitting blasting and a quantitative evaluation methodology for blast effect were established. Meanwhile, an optimized control strategy was proposed that leverages the synergistic effects of grouting reinforcement, segmented stemming, and decked charge configurations. Field validation tests confirmed the feasibility of this synergistic approach. Key findings reveal three dominant factors governing presplit blasting effectiveness: (1) the intersection angle () between natural fractures and the blast hole alignment, (2) fracture length (Lf), and (3) fracture spacing (d). As increases from 0° to 90°, the primary fractures' role transitions progressively from assisting to inhibiting the fracturing process. In contrast, the presplit fractures evolve morphologically from smooth, continuous linear/gentle-zigzag patterns to irregular, rough, and discontinuous X-shaped configurations. The influence of Lf intensifies with the increasing intersection angle (), while the smoothness and continuity of presplit fractures degrade substantially. The detrimental effect of primary fractures diminishes with greater fracture spacing (d). By implementing grouting reinforcement combined with segmented plugging stemming and spaced charging, both rock mass homogeneity and uniformity of explosive energy distribution in presplitting holes are markedly enhanced, ultimately generating distinct presplit fractures along the full blast hole length at a 70% fracture rate.During roof presplitting blasting for auxiliary air inlet and roof cutting gob-side entry retaining at Pingshu Coal Industry's 8213 working face, blast-induced fractures exhibit random propagation patterns and deviate from presplitting holes alignment due to the influence of pre-existing fractures. The presplit fractures exhibit discontinuous, rough, and serrated morphologies, resulting in rock masses interlocking that hinder effective separation along the presplitting hole plane and delay pressure relief. Consequently, the surrounding rock of the gob-side entry retaining maintains prolonged high-stress conditions, leading to significant deformations. To enhance roof-cutting effectiveness in fractured rock masses through presplitting blasting, this study employs the discrete element particle expansion method to numerically investigate how characteristic parameters of fracture distribution influence presplit fracturing outcomes. Furthermore, a multi-parameter coupling simulation system for rock mass presplitting blasting and a quantitative evaluation methodology for blast effect were established. Meanwhile, an optimized control strategy was proposed that leverages the synergistic effects of grouting reinforcement, segmented stemming, and decked charge configurations. Field validation tests confirmed the feasibility of this synergistic approach. Key findings reveal three dominant factors governing presplit blasting effectiveness: (1) the intersection angle (β) between natural fractures and the blast hole alignment, (2) fracture length (Lf), and (3) fracture spacing (d). As β increases from 0° to 90°, the primary fractures' role transitions progressively from assisting to inhibiting the fracturing process. In contrast, the presplit fractures evolve morphologically from smooth, continuous linear/gentle-zigzag patterns to irregular, rough, and discontinuous X-shaped configurations. The influence of Lf intensifies with the increasing intersection angle (β), while the smoothness and continuity of presplit fractures degrade substantially. The detrimental effect of primary fractures diminishes with greater fracture spacing (d). By implementing grouting reinforcement combined with segmented plugging stemming and spaced charging, both rock mass homogeneity and uniformity of explosive energy distribution in presplitting holes are markedly enhanced, ultimately generating distinct presplit fractures along the full blast hole length at a 70% fracture rate.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 62 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.008
Research and Application of Presplitting Blasting Construction Technology Using Coupled Charging with Wide Hole Spacing and Low-energy Bulk Emulsion Explosives
CHEN Yun-cheng, YANG Zhi-yong, GUAN Wei-ming, ZHAO Ming-sheng, ZHU Wei, LIU Gang, LI Tie-long, and HOU De-feng
Presplit blasting serves as an essential technique for maintaining optimal excavation profile integrity and enhancing rock mass stability in open-pit mining operations. Traditional presplit blasting techniques are plagued by excessive drilling requirements, prohibitive construction expenses, and suboptimal operational efficiency. To address these technical and economic constraints, this study introduces and comprehensively examines an innovative technique: wide-spacing presplit blasting with low-power, bulk-loaded explosives and a coupled-charging configuration. This investigation focuses on the engineering of metamorphic sandstone slopes at the 380 platform on the left side of a specific open-pit mining operation, which serves as the research context for the study. This study addresses the critical technical challenges in implementing the novel method under conditions of high rock hardness (strength factor f=12~16) and intact rock mass structure, focusing on two key aspects: the diminished superposition effect of stress waves and the enhanced difficulty of crack coalescence resulting from significantly increased borehole spacing (18~25 times the borehole diameter, e. g., 3.0 m spacing for a 140 mm diameter holes); and the stringent requirements for precise energy distribution and optimal utilization of the “air wedge effect” imposed by the unique charging configuration that combining bottom-coupled charges with upper decked air gaps. Based on stress wave propagation theory and explosion gas quasi-static pressure mechanisms, this study develops an optimized blasting design featuring bottom-coupled charges for effective crack initiation combined with upper decked air gaps to facilitate crack propagation, while employing an electronic detonator-based precision delay initiation network to ensure prioritized presplit hole detonation and coordinated inter-hole stress field development. Field application demonstrated outstanding performance metrics: the technique achieved an average half-hole preservation rate of 85.2% while maintaining presplit surface deviation within 8.7 cm. The innovative approach yielded substantial economic benefits, including a 50% reduction in drilling volume, an 84% cost saving through electronic detonator substitution for detonating cord, and more than fivefold efficiency gains via bulk explosive loading systems, collectively reducing comprehensive costs per square meter by 46.6%. This advanced wide-spacing, low-power, bulk-loaded emulsion explosive coupled charge presplit blasting technology represents a technically sophisticated, economically viable, and operationally reliable solution that effectively addresses conventional method limitations. The successful implementation establishes a replicable framework for slope control blasting in analogous open-pit mining environments, demonstrating significant potential for widespread engineering applications.Presplit blasting serves as an essential technique for maintaining optimal excavation profile integrity and enhancing rock mass stability in open-pit mining operations. Traditional presplit blasting techniques are plagued by excessive drilling requirements, prohibitive construction expenses, and suboptimal operational efficiency. To address these technical and economic constraints, this study introduces and comprehensively examines an innovative technique: wide-spacing presplit blasting with low-power, bulk-loaded explosives and a coupled-charging configuration. This investigation focuses on the engineering of metamorphic sandstone slopes at the 380 platform on the left side of a specific open-pit mining operation, which serves as the research context for the study. This study addresses the critical technical challenges in implementing the novel method under conditions of high rock hardness (strength factor f=12~16) and intact rock mass structure, focusing on two key aspects: the diminished superposition effect of stress waves and the enhanced difficulty of crack coalescence resulting from significantly increased borehole spacing (18~25 times the borehole diameter, e. g., 3.0 m spacing for a 140 mm diameter holes); and the stringent requirements for precise energy distribution and optimal utilization of the “air wedge effect” imposed by the unique charging configuration that combining bottom-coupled charges with upper decked air gaps. Based on stress wave propagation theory and explosion gas quasi-static pressure mechanisms, this study develops an optimized blasting design featuring bottom-coupled charges for effective crack initiation combined with upper decked air gaps to facilitate crack propagation, while employing an electronic detonator-based precision delay initiation network to ensure prioritized presplit hole detonation and coordinated inter-hole stress field development. Field application demonstrated outstanding performance metrics: the technique achieved an average half-hole preservation rate of 85.2% while maintaining presplit surface deviation within 8.7 cm. The innovative approach yielded substantial economic benefits, including a 50% reduction in drilling volume, an 84% cost saving through electronic detonator substitution for detonating cord, and more than fivefold efficiency gains via bulk explosive loading systems, collectively reducing comprehensive costs per square meter by 46.6%. This advanced wide-spacing, low-power, bulk-loaded emulsion explosive coupled charge presplit blasting technology represents a technically sophisticated, economically viable, and operationally reliable solution that effectively addresses conventional method limitations. The successful implementation establishes a replicable framework for slope control blasting in analogous open-pit mining environments, demonstrating significant potential for widespread engineering applications.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 58 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.007
Study on Parameter Optimization of Presplitting-smooth Combined Blasting for Soft Rock Roadway Excavation
HUANG Gang, CHEN Huan-xuan, WANG Liang, CHEN Chen, YANG Ming, and HUANG Zhao-wei
To address the technical challenge of blast-induced overbreak at tunnel crowns during soft rock roadway excavation, this study proposes an optimized presplit-smooth blasting synergistic method. Theoretical analysis grounded in wave impedance principles demonstrates that the wave impedance disparity between pre-split cracks and surrounding rock creates a high-reflectivity interface, fundamentally altering stress wave propagation dynamics. When the stress wave reaches this interface, most of its energy is reflected, with only a small portion transmitted, resulting in substantial attenuation of wave intensity. This phenomenon transforms the initially transient, intense impact energy into a millisecond-scale, gradually released load, effectively mitigating energy superposition from subsequent stress waves and preventing cumulative damage within the rock mass, thereby significantly improving the dynamic stability of the geological structure. Numerical simulation results demonstrate that the synergistic method outperforms conventional smooth blasting by effectively confining the damage zone within the presplit fracture boundary, resulting in a remarkable reduction in crown damage depth to 0.3 m. Furthermore, this approach substantially decreases peak particle velocity (PPV) while transforming the loading profile from a transient sharp-rise/slow-decay' impact to a more controlled millisecond-level delayed-release' pattern featuring gradual pressure buildup and deferred peak intensity. Field implementation of the optimized synergistic scheme in the kaolinized diorite porphyry roadway at the -350 m level of the Gushan Iron Mine demonstrated exceptional contour control, maintaining intact surrounding rock in weak interlayer zones without spalling or collapse. The study verifies that the presplit-smooth blasting synergistic method, leveraging stress barrier effects and meticulous parameter optimization, achieves a substantial reduction in blast-induced damage and vibration while effectively mitigating overbreak in soft rock roadway excavation.To address the technical challenge of blast-induced overbreak at tunnel crowns during soft rock roadway excavation, this study proposes an optimized presplit-smooth blasting synergistic method. Theoretical analysis grounded in wave impedance principles demonstrates that the wave impedance disparity between pre-split cracks and surrounding rock creates a high-reflectivity interface, fundamentally altering stress wave propagation dynamics. When the stress wave reaches this interface, most of its energy is reflected, with only a small portion transmitted, resulting in substantial attenuation of wave intensity. This phenomenon transforms the initially transient, intense impact energy into a millisecond-scale, gradually released load, effectively mitigating energy superposition from subsequent stress waves and preventing cumulative damage within the rock mass, thereby significantly improving the dynamic stability of the geological structure. Numerical simulation results demonstrate that the synergistic method outperforms conventional smooth blasting by effectively confining the damage zone within the presplit fracture boundary, resulting in a remarkable reduction in crown damage depth to 0.3 m. Furthermore, this approach substantially decreases peak particle velocity (PPV) while transforming the loading profile from a transient sharp-rise/slow-decay' impact to a more controlled millisecond-level delayed-release' pattern featuring gradual pressure buildup and deferred peak intensity. Field implementation of the optimized synergistic scheme in the kaolinized diorite porphyry roadway at the -350 m level of the Gushan Iron Mine demonstrated exceptional contour control, maintaining intact surrounding rock in weak interlayer zones without spalling or collapse. The study verifies that the presplit-smooth blasting synergistic method, leveraging stress barrier effects and meticulous parameter optimization, achieves a substantial reduction in blast-induced damage and vibration while effectively mitigating overbreak in soft rock roadway excavation.
- Apr. 13, 2026
- Blasting
- Vol. 43, Issue 1, 49 (2026)
- DOI：10.3963/j.issn.1001-487x.2026.01.006
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