Current catalogue

  • Numerical Analysis and Experimental Study on Failure Process of Drilling and Blasting in Reinforced Concrete Columns

    HUANG Xiao-wu;XIE Xian-qi;JIA Yong-sheng;LIU Chang-bang;YAO Ying-kang;WU Yue;Wuhan Explosion & Blasting Co.,Ltd.;State Key Laboratory of Precision Blasting,Jianghan University;Hubei Key Laboratory of Blasting Engineering,Jianghan University;

    In blasting demolition projects of housing buildings, reinforced concrete columns serve as the primary load-bearing structural elements and consequently represent the most frequently targeted components for controlled demolition.The effectiveness of reinforced concrete column demolition through blasting operations plays a pivotal role in ensuring structural instability and controlling the overall collapse mechanism.The evolution of modern reinforced concrete columns, characterized by increased cross-sectional dimensions, higher reinforcement densities, and enhanced material strengths, has significantly elevated the technical complexity of the design of blasting parameters and the protection of flying rocks.The Particle Blasting Method coupled with the Finite Element Method(PBM-FEM) was employed to simulate the dynamic process of explosion impact loading and explosion gas escaping from the borehole through the high-speed motion collision of particles.Full-scale 1∶1 physical model tests were conducted using industrial electronic detonators to accurately replicate the blasting demolition process of high-rise building structural members.The research reveals critical insights into the failure mechanisms and damage propagation characteristics of reinforced concrete columns under controlled demolition conditions.The results show that the explosion gas escapes from the orifice and reduces the utilization rate of explosive energy due to the limited constraint effect of the blocking material on the side of the blast hole.The severity of concrete spalling on the surface of the column is left and right sides > front side > back side.The direction of the minimum resistance line is the main direction to induce concrete damage and throwing.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 902K]

  • Effect of Length-to-diameter Ratio on Overpressure Characteristics of Methane/Air Premixed Explosions

    CHENG Jian-hua;BAO Wen-wen;YANG Xiao-lin;DING Shuai-dong;WENG Ying-kang;ZHANG Zi-jun;School of Civil Engineering, Henan Polytechnic University;International Joint Research Laboratory of Henan Province for Underground Space Development and Disaster Prevention;China Railway 16th Bureau Group Co.,Ltd.;

    To explore the influence of ignition position change on overpressure characteristics of methane/air premixed explosion under different equivalence ratios, several tests with varying length-to-diameter and equivalence ratios on the rise rate of peak overpressure and positive pressure duration were carried out through a self-built explosion test system.The main influencing factors affecting the pressurization characteristics of methane/air premixed explosion were analyzed by the dimensional analysis method, and the calculation formulas of rise rate of overpressure peak and positive pressure during methane/air premixed explosion were proposed.The results show that the rise rate of the overpressure peak increases with the increase of the equivalence ratio, and the increase in length-to-diameter ratio makes the rise rate decrease gradually, which is different from the attenuation rate.The positive pressure duration is gradually prolonged with the rise of the length-to-diameter ratio.However, the maximum positive pressure duration corresponds to different equivalence ratios with the length-to-diameter ratio changes.Furthermore, the calculation formulas of the rise rate of overpressure peak and positive pressure duration of methane/air premixed explosion are obtained by the dimensional analysis method, and the feasibility of the formulas is verified by comparing the experimental values with the theoretical values.It was found that methane/air premixed explosion is significantly affected by the ignition position and equivalence ratio, which can provide a reference for the power evaluation and safety control of methane explosions.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 790K]

  • Analytical Solution and Influencing Factors of Dynamic Response of Deep-buried Diversion Tunnel with Circular Composite Lining under Transient Disturbance by P-wave

    LI Mei;LU Yu-jia;MEI Wan-quan;HAN Gao-sheng;CHEN Guang-hai;ZHAO Ming-sheng;KE Chang-jun;REN Gao-feng;School of Resources and Environmental Engineering,Wuhan University of Technology;Ministry of Education KeyLaboratory of Key Non-metallic Mineral Resources Green Utilization,Wuhan University of Technology;Hubei Key Laboratory of Mineral Resources Processing and Environment,Wuhan University of Technology;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Me

    Blasting excavation generates transient P-waves that significantly impact tunnel stability.For water-filled diversion tunnels, the dynamic response of the surrounding rock differs from conventional dry tunnels.Most existing analytical studies focus on the steady-state solution and single-lined tunnels, rarely accounting for composite linings or the presence of water.This paper investigates the transient stability response of deep-buried circular composite lining diversion tunnels under transient P-wave disturbances.The fluid within the tunnel is treated as a distinct medium, and the tunnel-lining interface is considered a non-ideal contact surface.By applying Fourier synthesis, wave function expansion, and trapezoidal quadrature formula, an analytical solution is derived.Validation through comparison with existing literature demonstrates the method′s effectiveness.The study analyzes the effects of Poisson′s ratio of surrounding rock, the non-ideal interface′s elastic coefficient, and the disturbance′s loading duration on the dynamic stress concentration coefficient.Results indicate that the compressive stress concentrations occur at the roof and floor, while tensile counterpart concentrations appear at the two sidewalls during dynamic disturbance.As Poisson′s ratio increases, there is a transition from tensile to compressive stress concentration, with a gradual degree in compressive stress intensity.Poor contact between the rock mass and liner induces oscillations in the stress time-history curve.The dynamic response converges accordingly as the elastic coefficients of an imperfect interface approach those of a perfect interface.With increasing blasting load duration, peak dynamic stress around the roof and floor initially rises, then stabilizes, while stress at the sidewalls initially decreases before leveling off.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 633K]

  • Experimental Study on Optimization of Presplitting Blasting Parameters for Water-adjacent Slopes

    ZHONG Dong-wang;TAO Hao-hao;LI Lin-na;LI Teng-fei;HE Li;SI Jian-feng;WAN Jia-wei;GAO Han;College of Science, Wuhan University of Science and Technology;Hubei Intelligent Blasting Engineering Technology Research Center;China Railway Fourth Institute Group Engineering Operation and Maintenance Limited Liability Company;

    Pre-splitting blasting has been widely employed in river channel slope excavation to effectively mitigate damage to the retained rock mass, reduce blast-induced vibrations, and optimize blasting parameters for water-saturated slopes.Investigation of reasonable parameters for pre-splitting blasting in such conditions is important for river channel excavation projects.Based on geometric, physical, and dynamic similarity principles, an experimental model for pre-splitting blasting water-saturated slopes was designed, utilizing concrete as a substitute for red sandstone and detonators instead of emulsified explosives.The quality of pre-split crack formation, slope face shaping, and retained rock mass damage were evaluated under various conditions.The results showed that the pre-split crack formation quality and slope shaping quality significantly improved.The damage to the retained rock mass was reduced by 24.86% when the hole diameter increased from 0.8 cm to 1.2 cm.Field test results indicated that the optimal blasting effect can be achieved with a pre-split hole diameter of 115 mm and a hole spacing of 80 cm in a practical application of pre-splitting blasting for water-saturated slopes when the geological conditions involve medium-hard rocks.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 1195K]

  • Experimental Study on Crack Propagation Characteristics of Blasting-Induced Fracturing in Low-permeability Coal Samples

    ZHANG Fei-yan;DUAN Xiao-yan;HAN Ying;College of Safety Science and Engineering,Henan Polytechnic University;Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization;School of Energy Science and Engineering,Henan Polytechnic University;Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region(Henan Province);Science and Technology R&DPlatform of Emergency Management Ministry for Deep Well Ground Control and Gas Extraction

    Pre-split blasting has emerged as a crucial technique for enhancing the permeability of low-permeability coal seams and improving gas drainage efficiency.While extensive research has focused on the effects of factors such as blast hole configuration, charge structure, charge coefficient, explosive quantity, and the propagation dynamics of blasting stress waves, limited attention has been given to fracture expansion characteristics through numerical simulations.Furthermore, experimental investigations into crack propagation remain scarce.This study addresses these gaps by examining low-permeability coal samples from a specific mine, employing small-dose coupled charge blasting technology combined with computerized tomography scanning technology.The experimental approach enabled the acquisition of macroscopic damage characteristics and three-dimensional crack distribution patterns post-blasting, facilitating an in-depth analysis of internal crack expansion under blasting stress.Key findings demonstrate the feasibility of utilizing detonating explosives instead of conventional explosives for small-scale coal sample blasting experiments with low-dose coupled charges.The results reveal that:(1) a larger blast hole diameter correlates with diminished crack propagation and permeability enhancement under constant charge quantity and tamping pressure;(2) tamped charges outperform loose charges when blast hole diameter and charge quantity are held constant;(3) an optimal charge quantity exists for fracture propagation, with excessive amounts proving counterproductive.Specifically, for the standard-sized low-permeability coal samples examined, a charge quantity of 25 mg yielded optimal results, producing a crack volume ratio of 12.79% and a single crack volume of 20 135.03 mm, followed closely by a 20 mg charge.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 443K]

  • Study on Dynamic Characteristics and Failure Characteristics of Magnetite under Impact Load

    NIU Jun-chao;LI Ji-min;MEI Lin-fang;REN Gao-feng;GE Yong-xiang;ZHANG Cong-rui;LU Xi-kui;ZHAO Liang;SATIMIN NOER REFKY ADI NATA;School of Resources and Environmental Engineering,Wuhan University of Technology;Chengchao Mining Company of WlSCO Resources Group;WISCO Resources Group Corporation Limited;Key Laboratory of Green Utilization of Key Non-metallic Mineral Resources,Wuhan University of Technology;Jingmen Natural Resources and Planning Bureau;

    To investigate the energy evolution and failure patterns of magnetite during blasting and to minimize the impact of blasting disturbances on the stability of pillars and surrounding rocks, a series of multi-stage strength impact tests were conducted on magnetite samples using a Split Hopkinson pressure bar(SHPB) apparatus.The dynamic response characteristics of magnetite were analyzed, focusing on parameters such as dynamic peak compressive strength, failure modes, fragmentation size, and energy dissipation density under varying strain rates.The results show that magnetite′s dynamic peak compressive strength and energy dissipation density increase exponentially with the increase in strain rate.At the same time, the crushing size decreases exponentially, demonstrating a strong strain-rate dependency.The failure process of magnetite can be divided into three stages: crack compaction, elastic deformation, and crushing.The dynamic increase factor(DIF) also increases with the increase in strain rate.The failure mode of magnetite transitions from splitting failure at lower strain rates to crushing failure at higher strain rates as crack interactions intensify.Therefore, when blasting rock breaking is applied to magnetite mining, it is crucial to balance impact strength and energy dissipation to enhance crushing efficiency while meeting the required fragmentation standards.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 506K]

  • Study on Titanium Fire Suppression Technology in Shaped Charge Cutting of Titanium Alloys

    WEI Zhong;WANG Meng;XIE Qiang;LI Fa-yao;WANG Tian-xi;WANG Yi-xuan;XUAN Hai-jun;HE Ze-kan;School of Chemical and Blasting Engineering, Anhui University of Science and Technology;High-speed Rotating Machinery Laboratory, Zhejiang University;

    During aero-engine casing containment tests, the explosive separation method used to achieve the constant-speed fly-off of titanium alloy blades often produces a bright titanium fire phenomenon.This titanium fire obstructs high-speed camera recording of the blade fly-off process.To address this issue, this study analyzed the mechanism of titanium fire generation and proposed a barrier layer method to suppress titanium fire during shaped energy cutting of titanium alloys.Numerical simulations using the Euler algorithm in AUTODYN were conducted to evaluate the blocking effect of the barrier layer and its feasibility for titanium fire suppression.Experimental investigations were then performed to quantitatively assess the brightness reduction of titanium fire, comparing the effectiveness of four barrier materials.The results indicate that 0.1mm thick aluminum and titanium tin foil achieve titanium fire suppression rates of 29.5% and 24%,respectively, demonstrating moderate effectiveness.A 0.1 mm thick copper sheet shows poor performance with a suppression rate of only 4.3%,while a 0.1 mm thick aluminum silicate coating exhibits the best performance, achieving a suppression rate of 70.9%.This study has summarized the mechanism of titanium fire suppression suing barrier layers during shaped energy cutting of titanium alloy plates and validated the feasibility of the barrier layer method.The findings can provide a practical approach for titanium fire elimination in explosion separation processes involving shaped energy cutting of titanium alloys.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 311K]

  • Control Technology for Oversized Fragments in Engineering Blasting at Pingtanyuan Pumped-storage Power Station Project

    TAN Zhan-zhi;ZHANG Guang-hui;CHEN Ming;ZHANG Jia-tuo;CHENG Yuan-long;State Key Laboratory of Water Resources Engineering and Management, Wuhan University;Luotian Pingtanyuan Pumped Storage Co.,Ltd.of Hubei Energy Group;

    The occurrence of oversized fragments during blasting operations significantly increases the cost of blasting, crushing, and hauling expenses.This study addressed the slab′ phenomenon observed in the blasting of intact hard rock at the Pingtanyuan Pumped Storage Power Station, where the oversized fragments of the surface blasting area was up to 6 m×5 m×2.5 m.Through comprehensive mechanism analysis, the investigation indicated that the quality of the stemming was the key reason for forming large fragments at the upper part.Meanwhile, the mechanism of its influence lies in the over-long stemming length of the original blasting scheme, which resulted in a low charge center, leading to insufficient energy distribution at the top of the blast hole.Furthermore, an oversized blasting fragments control measurement based on stemming quality optimization was proposed.The stemming length was optimized from 3～4 m to 2.1～2.4 m using a time-sharing piecewise calculation method and the optimization principle, which allowed the part of the stemming structure to rush out of the blast hole.Besides, the decontaminated rock chips were used as stemming material.The results show that the optimized scheme prevented the occurrence of the slab phenomenon, significantly reduced boulder rates, and saved rock breakage costs.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 323K]

  • Study on Internal Rock Mass Movement Trajectory and Muckpile Distribution during Bench Blasting

    LI Zhi-heng;BAI Jun;JIN Chang-yu;CHEN Li-jun;Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines, Northeastern University;Lanxian Mining Co.,Ltd.,TIsco Group;China Railway 19 Bureau Group Mining Investment Co.,Ltd.;

    As a main mean of open-pit mining, bench blasting is still an irreplaceable production method at present and even in the future.By deeply analyzing the measured data of bench blasting and using 3DEC software to simulate the bench blasting process, the internal rock mass movement trajectory and muckpile distribution during the bench blasting process were revealed.The research results show that the monitoring points generally rose along the vertical direction first and then fell during the blasting process.Among them, the movement of the monitoring points on the upper part of the monitoring hole were more obvious in the vertical direction, rising to a certain height and then quickly moving vertically downward.While the monitoring points on the lower part of the monitoring hole mainly moved forward in the horizontal direction, and the vertical direction movement is relatively weak.At the same time, in order to study the spatial distribution of the muckpile, the bench in the research area were divided into six parts, as Ⅰ～Ⅵ.Besides, the main part(0～40 m) of the muckpile was divided into four regions, as A,B,C and D.According to the simulation results, it can be found that the Ⅴ rock mass accounts for the most in region A(muckpile 0～10 m),which is as high as 41.7%.The Ⅰ～Ⅴ rock mass distribution is relatively even in region B(muckpile 11 m～20 m).The Ⅰ～Ⅲ rock mass accounts for 43.1%,37.5% and 19.3%,respectively, and the Ⅳ rock mass accounts for a very small part in region C(muckpile 21～30 m).It is basically composed of the Ⅰ rock mass in region D(muckpile 31～40 m) at the forefront of the blast muckpile, which accounts for 95%.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 508K]

  • Study on Crack Propagation Law Induced by Millisecond Delay Blasting with Different Hole Spacing

    CAO Yong-bang;HUANG Jun-hong;WANG Zi-xu;CHEN Yang-long;ZHANG Teng-sheng;LI Xin-ping;School of Civil Engineering and Architecture,Wuhan University of Technology;School of Resources and Environmental Engineering,Wuhan University of Technology;Sanya Science and Education Innovation Park,Wuhan University of Technology;

    A large-area concrete site was prepared to eliminate the boundary effects to investigate the propagation law of detonation-induced cracks in differential blasting under varying hole spacing.Multiple sets of linear three-hole and cross-five-hole model tests were conducted using electronic detonators and detonating cords as the blasting sources.The propagation length, direction, and crack arrest position of detonation cracks were recorded under different blasting parameters.The key factors affecting crack propagation were identified by combining the experimental results with the theory of sequential controlled blasting.The results indicate that in the three-hole model, a through-crack forms between the blast holes when the middle hole detonates first, followed by the two side holes.However, as the hole distance increases, the crack becomes increasingly irregular.When the distance reaches 25 times the hole diameter, the crack fails to penetrate and no longer propagates along the direction of the blast holes.In the cross five-hole model, a through-crack can only form when the spacing is within 20 times the hole diameter.The crack generated by the first blast tends to propagate towards the nearest subsequent hole.Still, it does not follow a straight path, exhibiting deflection due to the influence of the additional holes.Therefore, to achieve straight cracks along the contour surface in practical engineering, it is crucial to adjust the timing and control blasting parameters based on specific hydrogeological conditions to fully utilize the void effect and the detonation timing difference.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 445K]

  • Numerical Simulation and Application of Energy Dissipation Blasting for Relatively Intact Hard Rock

    CHEN Yu-quan;LI Da-zhong;LI Ming-ze;CHEN Ming;China International Water & Electric Corp;State Key Laboratory of Water Resources Engineering and Management, Wuhan University;

    A novel energy dissipation blasting technique based on water coupling is proposed to explore new methods for rapid excavation of spillway protection layers in hydropower stations under relatively intact hard rock conditions.This method specifically addresses the excavation requirements of the Nam Kong 1 Hydropower Station spillway in Laos.By increasing borehole pressure, the technique generates stronger stress, which is advantageous for excavating hard rock formations.Simulation analysis using LS-DYNA software demonstrates that coupling water-charged explosives with a blocked borehole bottom amplifies the peak load on the borehole walls and extends the explosive load duration, thereby improving the fragmentation of harder rock at the borehole bottom.Results indicate that the combination of bottom-hole blockage and water-coupled charges increases lateral damage depth and prolongs load application time, thus achieving more effective excavation and formation in relatively intact hard rock.Comprehensive evaluations based on numerical simulations and field test parameters confirm that this approach significantly improves the quality of excavation and formation of the first-stage stilling basin floor in practical engineering applications.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 481K]

  • Research on Burn Cut Blasting Technology Combining Long and Short Holes for Small-section Tunnels

    WANG Lei;GAO Yu-fan;FU Hong-xian;MU Yuan-hong;LIU Yan;ZUO Chun-yuan;LI Qing-jing;China Railway Third Bureau Group No.5 Engineering Co.,Ltd.;College of Civil Engineering, University of South China;School of Civil Engineering, Beijing Jiaotong University;

    To enhance excavation speed in small-section tunnels and address the limitations of oblique and burn cut blasting techniques, a new burn cut blasting method combining long and short straight holes is proposed based on rock blasting theory, stress wave rock breaking theory, and sacrificial blasting theory.This method improves the burn cut blasting approach with equal resistance lines, eliminating the need for empty holes.The blasting parameters and cavity formation process are discussed in detail.Through field tests and the use of different detonators and cutting layouts, the performance of various cutting methods was evaluated in terms of blasting advance, powder factor, and over-excavation and under-excavation.The results show that the proposed burn cut blasting method is not constrained by tunnel cross-sectional area, allowing for independent hole depth design and optimal delay intervals to achieve staged and layered blasting.This technique enhances the role of free surfaces in the cutting process, reducing the minimal resistance line in deep holes.The resulted cavity is a regular rectangular shape, increasing blast hole utilization from 78.5% to 89.3%.Field tests show that, in small-section tunnel blasting, this method increases the advance from 1.6～2.2 m to 2.2～2.5 m compared to traditional inclined-hole cut blasting.Over-excavation was further reduced by 20%～30% when the displacement of surrounding holes remained within 10cm.The proposed cutting method effectively controls costs, improves operational efficiency, and offers both technical and economic advantages with improved blasting outcomes.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 314K]

  • Safety-controlled Blasting Technology for High-steep Slopes in Open-pit Mines

    CHEN Jing-jing;LIN Wan-qing;LIU Yi;Hongda Blasting Engineering Group Co.,Ltd.;Beijing CAS-Mechanics Blasting Co.,Ltd.;

    The original stope benches of Dahuangshan Open-pit Mine were in disarray, with pumice between benchs and steep slope conditions.Following blasting operations, a crushing system was introduced to improve rock fragmentation efficiency, significantly increasing potential safety risks near high and steep slopes.This study researched safe blasting techniques and protective measures for slopes in open-pit mines to ensure slope safety during blasting construction.Active protection methods were proposed, including limiting instantaneous charge to 200 kg, aligning the blasting direction parallel to the slope, and preserving approximately 5 m of rock wall along the slope edge.Protective infrastructure was enhanced by installing two protective nets on a cleaning platform mid-slope, excavating a 7 m-deep and 20 m-wide stone protection ditch at the foot of the slope, building a 2 m-high stone protection wall using crushed stones outside of the ditch, and erecting a 2 m-high isolation net outside the protection wall.These safety measures were complemented by auxiliary monitoring methods to enhance the safety of blasting operations and protect the crushing system.Field inspections confirmed that the construction methods effectively ensured the stability of the high-steep slopes and minimized risks during blasting.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 273K]

  • Analysis of Collapse Process of Frame-shear Wall Structures with Different Incision Patterns during Blasting Demolition

    ZHANG Yi-xiang;ZHAO Guo-chen;LIN Shi-bin;WANG Yu-jin;LIU Chang-bang;State Key Laboratory of Precision Blasting,Jianghan University;Hubei Provincial Key Laboratory of Blasting Engineering,Jianghan University;School of Digital Construction and Blasting Engineering,Jianghan University;Wuhan Blasting Co.,Ltd.;

    Based on the blasting demolition of a 7-storey frame-shear wall structure in Wuhan, this study investigates the impact of different incision patterns on the collapse process.A refined finite element numerical model was established using ABAQUS,with steel and concrete supporting columns modeled separately and the upper collapse body modeled as a whole.This approach enables accurate simulation of the mechanical behavior of supporting columns while improving computational efficiency.A triangular incision form model was also developed and compared against the trapezoidal incision form used in the project.The stress distribution, recoil distance, and collapse motion characteristics of supporting columns under the two different incision forms were analyzed to explore their effects on the collapse process.Results indicate a high consistency between the numerical simulation and the actual collapse regarding timing, motion characteristics, and overall process, validating the modeling approach.Compared to the trapezoidal incision form, the triangular incision form features a lower center of gravity, causing the structure to tilt quickly around the incision vertex post-detonation.This leads to rapid failure of the rear-row support columns under large eccentric pressure.Consequently, the collapsed body makes ground contact faster, at a higher velocity and disintegrates more thoroughly.Additionally, the triangular incision generates greater horizontal kinetic energy, resulting in a larger recoil distance.This analysis highlights the significance of incision form selection in optimizing blasting demolition outcomes.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 434K]

  • Experimental Study on Effect of Different Protective Laying Materials on Dynamic Impact Resistance of Reinforced Concrete Slabs

    HUANG Qiu-yue;ZHONG Dong-wang;LI Teng-fei;YANG Zhi-long;HE Li;College of Science, Wuhan University of Science and Technology;Hubei Intelligent Blasting Engineering Technology Research Center;

    Reinforced concrete structures are usually subjected to explosion impact load, resulting in severe damage.Different protective materials are typically laid on reinforced concrete slabs to improve the explosion resistance.The experimental study on the explosion resistance of reinforced concrete slabs with different protective materials was conducted using the drop hammer test, and an accelerometer tested the impact of reinforced concrete.An embedded piezoelectric intelligent aggregate is used to monitor the internal damage signal of a reinforced concrete slab under the drop hammer impact load.The test results show that both carbon fiber reinforced matrix composites(CFRP) and polyurea can effectively protect the specimens in the single-layer reinforced structure, with an average decrease of 78.20% and 79.05% relative to reinforced concrete acceleration and 40.98% and 65.79% peak impact stress, respectively.Additionally, the average acceleration reduction of polyurea-concrete-CFRP(IPC),polyurea-CFRP-concrete(ICP),and CFRP-concrete-polyurea(CIP) compared with reinforced concrete slabs are 70.29%,77.46% and 79.85% in the composite protective structure, respectively.The average peak impact stress reduction is 32.73%,56.32%,and 51.07%,respectively, which can effectively protect the specimens and improve the impact resistance of concrete slabs.It can provide a reference for related engineering applications.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 642K]

  • Research on Blasting Demolition Technology for Partial Spans of Continuous Girder Bridges

    ZHENG Xuan-rong;REN Kai;LIU Rui;LI Shuai-liang;YUE Xue-ru;College of Architecture and Civil Engineering, Xi′an University of Science and Technology;Shan′xi Road and Bridge Group Blasting Engineering Co.,Ltd.;

    The blasting demolition of partial spans in continuous beam bridges frequently entails substantial risks of damage to the adjoining spans.To ensure the effective collapse and fragmentation of the bridge while safeguarding the integrity of adjacent spans, a case study was undertaken focusing on the blasting demolition of a damaged section of a continuous beam bridge in Ankang City.Using ANSYS/LS-DYNA software, numerical simulations were conducted to investigate the impact of water pressure blasting on the upper box girder and evaluate various collapse scenarios for the lower piers.These scenarios included row-by-row inclined collapse, span-by-span collapse, and center-to-both-sides collapse patterns.The optimal blasting scheme was identified by comprehensively evaluating three key parameters: structural fragmentation efficiency, collapse configuration, and induced vibration velocity during demolition.Based on these simulation findings, an optimized blasting design was developed, with subsequent safety verification conducted on the vibration velocities to ensure structural integrity and operational safety.The results demonstrate that implementing water pressure blasting in the upper box girder successfully achieved substantial structural fragmentation while effectively controlling debris dispersion and minimizing potential impacts on neighboring spans.Through a strategic approach involving the conversion of the continuous beam into a supported configuration prior to demolition, coupled with a sequential detonation protocol initiating at the main beams of adjacent spans followed by row-by-row inclined collapse of the lower piers, the proposed scheme successfully achieved controlled bridge demolition.This methodology ensured optimal structural fragmentation while reducing vibration velocities within safe thresholds, effectively protecting adjacent spans.The field implementation results aligned well with the numerical simulations, as evidenced by the controlled collapse process and satisfactory fragmentation patterns observed during the on-site blasting operation.No significant damage was observed in the proximate piers.The peak maximum vibration velocity recorded at the monitoring points in the numerical simulation was 3.58 cm/s, closely aligning with the field-measured value of 3.96 cm/s, demonstrating the simulation results′ reliability.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 472K]

  • Current Situation and Prospect of Intelligent On-site Mixed-loading Vehicles

    AN Zhen-wei;ZHANG Xiao-yong;LI Yong;LIU Lei;China Gezhouba Group Explosive Co.,Ltd.;

    Since the concept of intelligent blasting was proposed, the on-site mixed explosive vehicles(MEVs) have struggled to meet the evolving demands of the field.Reviewing the development of MEVs abroad reveals that while developed countries have a higher proportion of on-site mixed explosives usage, their levels of automation and intelligence have progressed slowly, with only a handful of civil explosive giants proposing related concepts.In China, to meet the national requirements for intelligent mine construction, some civil explosive enterprises and MEV manufacturers have begun exploring intelligent upgrades and applications for MEVs, achieving notable technological breakthroughs.China Gezhouba Group Explosive Co.,Ltd.has developed an intelligent on-site mixed ANFO vehicle featuring precise borehole positioning, automatic blasting design acquisition, one-button charging, and automatic information collection.This article introduces this intelligent ANFO vehicle, detailing its key technologies: high-precision charging metering control systems, intelligent high-precision positioning, and smart loading systems.These advancements offer references for the intelligent development of similar explosive vehicles.The future direction for on-site MEVs is to achieve full intelligence and crewless operation, encompassing capabilities such as unmanned driving, automatic hole targeting, and smart charging.Ultimately, these vehicles aim to integrate seamlessly into the framework of safe and collaborative operations within the mining sector.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 263K]

  • A Calculation Method of Wall Pressure for Uncoupled Liquid Oxygen Explosion for Rock Fracturing

    ZENG Hua-heng;XIE Ye-long;HU Yan;CHEN Bi-gang;WEI Yong;HUO Xiao-feng;Zijin College of Geology and Mining,Fuzhou University;Institute of Explosive Technology,Fuzhou University;Zhongchang Nuclear Industry(Fujian)Construction Development Co.,Ltd.;Fujian Transportation Research Institute Co.,LTD.;

    Given the current lack of comprehensive research on the mechanism of rock fracturing by high-pressure gas, this study draws upon the research method used to determine peak pressure at the borehole wall in the drilling and blasting method.By analyzing the complete rock fracturing process through the liquid oxygen expansion method, a calculation model for the peak pressure at the borehole wall was derived from the shock tube theory, considering the changes in the rock medium and uncoupling coefficient.Using a dynamic strain tester, a concrete model experiment was conducted to measure the peak pressure at the borehole.Under fixed conditions of a 60 mm expansion tube diameter and four different apertures(75～120 mm),the peak pressure was measured.The test results show that, with the same liquid oxygen equivalent and rock medium conditions, the time to peak pressure increases linearly with the uncoupling coefficient, following the relationship t=230.6k-127.85.As the uncoupling coefficient increases, the peak pressure at the borehole wall decreases gradually, with the attenuation rate gradually slowing.A comparison between the experimental results with the theoretical calculations shows a similar trend in peak pressure attenuation with the uncoupling coefficient, confirming the reliability of the theoretical model.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 460K]

  • Study on Influence of Vibration-reduction Holes on Blast Vibration Mitigation in Underwater Blasting

    WAN Jia-wei;ZHONG Dong-wang;XU Shun-xiang;HE Li;LI Teng-fei;TAO Hao-hao;GAO Han;XU Xiao-xiao;College of Science, Wuhan University of Science and Technology;Hubei Province Intelligent Blasting Engineering Technology Research Center;

    Underwater blasting vibration poses significant challenges in mining engineering applications, particularly channel dredging, seaport, and bridge construction.This study investigates the vibration attenuation mechanism and propagation characteristics through damping borehole configurations.The attenuation law of underwater blasting damping holes was studied, and a comprehensive experimental program to analyze the blasting vibration signals and piezoelectric signals was conducted by comparing three scenarios: conventional blasting without damping measures, water-coupled damping holes, and air-coupled damping holes.The optimized borehole parameters included a 2 cm diameter, 5 cm spacing, 4 cm row spacing, and 17 cm depth, positioned 20 cm from the explosive source.Experimental results demonstrated that using underwater blasting damping holes can effectively reduce the peak vibration velocity of blasting.The average damping rate of water-coupled damping holes and air-coupled damping holes is 17.5% and 27.2%,respectively.Time domain analysis revealed a consistent correlation between piezoelectric signals and the peak vibration velocity.The damping mechanism primarily affected vertical vibration components, with effectiveness positively correlated with charge weight.Field validation tests confirmed an 18.1% vibration reduction, establishing the practical efficacy of the proposed damping borehole array.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 517K]

  • Blasting-induced Vibration Suppression Techniques for Close-proximity Undercrossing of Existing Tunnels

    JIA jia-yin;CAO Zhen-yang;ZHOU Shi-jun;WU Xiao-dong;GAO Xing;WU Hao-jun;GONG Min;Chongqing Zhonghuan Construction Co.Ltd.;University of Science and Technology Beijing;

    To mitigate blasting vibration during the excavation of a drainage tunnel located 2.30～3.10 m beneath an existing tunnel, an optimized blasting scheme using millisecond blasting by electronic detonators and a subsection in blasting holes was implemented.The field blasting scheme was initially adjusted based on the conventional blasting situation near the existing tunnel.This involved optimizing hole position parameters and reducing the number of holes.Before the formal blasting in the underpass section, a single-hole blasting test was then conducted near the excavation face to capture the vibration waveform and geological information.Using the linear superposition method, the vibration waveform of various delay intervals was analyzed to select the optimal delay interval.To further improve blasting performance and reduce the vibration of the cut blasting, the first blasting in the cut area was performed by using the subsection blasting in the hole.Field tests and calculations determined that the optimal delay times were 5 ms for the same row of cut holes or spreader holes, 40 ms between rows, and 3 ms for contour holes.The new blasting scheme was implemented and optimized in the field.When the drainage tunnel was excavated at a footage of 1.5 m through the existing tunnel, the maximum vibration of the road surface monitoring point at a distance of 3.10 m directly above was maintained below 4.0 cm/s, ensuring structure safety.Using electronic detonators for precise initiation and sectional blasting successfully controlled site vibration, protected adjacent structures, and provided valuable insights for similar future projects.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 503K]

  • Study on Prediction Formula of Peak Particle Velocity Induced by Open-pit Mine Blasting

    SHAO Lei;ZHANG Mei;DENG Ding;GUO Lian-jun;GAO Jiu-qing;ZHAO Xin;School of Architecture and Civil Engineering, Shenyang University of Technology;Xuanhua Vocational College of Science & Technology;China Railway 19 Bureau Group Mining Investment Co.,Ltd.;

    To enhance the accuracy of blasting vibration predictions in an open-pit mine stripping project, a new peak particle velocity(PPV) prediction formula is proposed, incorporating geological elevation differences and slope effects.Based on the principles of dimensional analysis, the traditional Sadovsky formula was modified by introducing the elevation difference(H) and slope coefficient(γ),resulting in a new prediction model(Formula 11).Notably, when H=0,the new formula reverts to the traditional Sadovsky formula, ensuring its reliability.A field vibration monitoring test was conducted in the mine, with 5 monitoring points at elevation differences of 0.222 m, 0.176 m, 0.865 m, 1.617 m, and 2.465 m.Using the TC-4850 blasting vibration meter, vibration data were recorded, and multiple predictions, including the Sadovsky and the newly proposed formula, were fitted using multivariate nonlinear regression.Results show that the proposed formula achieves the highest correlation coefficient(R~2=0.905),surpassing other models.Furthermore, the new formula exhibits improved prediction accuracy, with a maximum relative error of 20.85% and an average error of 8.11%,compared to 24.89% and 10.31% for the original Sadovsky formula.By considering the factors of elevation and slope, the proposed prediction formula significantly improves the precision of PPV predictions under complex terrain conditions, providing a scientific basis for blasting vibration control and safety management.Applying the specific scheme and data proves the effectiveness and practicality of the formula.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 190K]

  • Research on Disposal of Waste Ammunition

    WANG Sen-sen;Hunan Provincial Public Security Department Security Corps;

    The long burial time, severe corrosion and damage of waste ammunition pose extremely high safety risks.Improper handling or disposal of such unstable ordnance may lead to serious negative impact on society.Taking the disposal work of waste ammunition in Hunan Province as the research object, this paper summarized the main disposal methods, analysed the existing problems, and proposed countermeasures and suggestions to enhance the disposal capabilities.To explore the shortcomings of the current disposal methods, the characteristics of waste ammunition(such as types, age, and conditions) had been analysed by field research and relevant literature.The study reveals that China′s waste ammunition disposal system confronts several critical challenges, including:(1)insufficient technical expertise among disposal personnel;(2) inadequate development of specialized storage infrastructure;(3) scarcity of specialized disposal equipment;(4) technological limitations in destruction methodologies;(5) an underdeveloped regulatory framework and institutional mechanisms for disposal operations.To address these challenges, this study proposes a comprehensive set of countermeasures:(1) enhancing specialized personnel training programs to improve technical competencies;(2) upgrading construction standards for dedicated storage facilities to ensure safety and compliance;(3) deploying advanced disposal equipment to increase operational efficiency;(4) developing innovative destruction technologies through targeted research;(5) standardizing disposal mechanisms to establish robust regulatory frameworks.The conclusion indicates that implementing scientific and standardized waste ammunition disposal protocols holds critical importance for mitigating public safety risks and safeguarding civilian lives and property.Future development should prioritize to enhance technological innovation and systematic improve management frameworks.These dual focus areas will collectively elevate operational standards and efficacy in waste ammunition disposal practices.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 151K]

  • Knowledge Graph-based Q&A System for Blasting Safety Management in Open-pit Mines

    SUN Jia-yi;LI Ping-feng;GUAN Wei-ming;TAN Jie;ZHAO Ming-sheng;YU Hong-bing;WEN Ying-yuan;TANG Hong-pei;Xinjiang University;Xinjiang Hongda Blasting Engineering Co.,Ltd.;Hongda Blasting Engineering Group Co.,Ltd.;

    Safety management plays a vital role in blasting operations, and blasting safety is closely related to the processes of drilling, blasting, loading, transportation, and dumping, with significant interactions among these procedures.However, due to the diverse sources and complex structure of current blasting safety data, the lack of systematic integration poses challenges for on-site personnel to accurately acquire critical safety knowledge under complex working conditions.To address this issue, this study applies a BERT-BiLSTM-CRF-based method for entity recognition in the field of blasting safety management.The BERT pre-trained model is first used to obtain dynamic word embeddings, followed by optimal label sequence tagging using the BiLSTM-CRF model.A knowledge graph covering seven entity types and nine relationship types is constructed and stored using the open-source Neo4j graph database system.Experimental results show that the F_1-score for all entity types exceeds 60%,demonstrating that the proposed model significantly improves entity recognition accuracy compared to traditional models.Based on this, a knowledge graph-based Q&A system for blasting process safety management in open-pit coal mines is developed, enabling rapid querying of domain knowledge and efficient matching of various blasting processes with safety standards.With the support of this Q&A system, on-site engineers can make timely and informed decisions in complex blasting safety management scenarios.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 1069K]

  • Design and Application of a Virtual Simulation Teaching Platform for Blasting Experiment Teaching

    LI Hao-yang;SUN Qiang;YI Jin;CHEN Tian-tian;Standard Quota Research Institute of the Ministry of Housing and Urban Rural Development;Civil Engineering Experimental Center, China University of Mining and Technology,Beijing;Wuhan Hanyang Municipal Construction Group Co.,Ltd.;

    Blasting Engineering is a core course in urban underground engineering and mining engineering in universities, and teaching blasting experiments is an indispensable link in practical teaching.As explosive engineering has a characteristic of great danger, the traditional explosive engineering experiment construction is rugged enough to be carried out indoors, which inconveniences teaching.Therefore, more and more schools rely on virtual simulation platforms.According to the teaching idea and demand of explosive engineering virtual simulation, this paper builds a virtual simulation teaching platform for blasting experiment teaching.Unity3D,a development tool for virtual simulation systems, was utilized to ensure high compatibility when running on different platforms.Meanwhile, the 3DS Max and Maya were applied to build and improve a realistic model.Furthermore, problems like slow loading speed and non-realistic animation through the cloud rendering technology were solved.The software ANSYS was used to simulate the propagation mechanism of blasting vibration waves in different rock layers better to reflect the blasting vibration waves in practical engineering.Finally, the wave field cloud map was saved as a snapshot in the virtual simulation system, and virtual simulation experiments of blasting vibration were carried out.The practice and application results show that the virtual simulation experiment platform can enable students to participate in the experiments of explosive engineering independently and deeply and improve students′ experimental experience and practical innovation ability.

    2025 02 v.42;No.176 [Abstract][OnlineView][Download 387K]
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