To systematically reveal the influence of laws of microwave radiation parameters (power, time) on the degradation of the mechanical properties of iron ore and the energy dissipation mechanism, and to improve the crushing efficiency of iron ore, this iron ore from Sishanling in Liaoning Province is the research object. By adopting a method combining microwave pretreatment, multi-scale mechanical tests, and microscopic tests, this thesis conducts static and dynamic impact tests as well as XRD tests on iron ore samples under different microwave actions. By analyzing the mechanical properties of iron ore subjected to various microwave treatments and utilizing the principles of energy conservation, this study elucidates the damage evolution characteristics and the laws governing energy evolution of iron ore under the coupled action of microwave and mechanical forces. The research results show that: (1) With an increase in microwave power and irradiation time, the sample mass decreases slightly, and the longitudinal wave velocity, uniaxial compressive strength, and elastic modulus exhibit a linear degradation trend. Microscopic tests have confirmed that the damage is caused by thermal stress cracking, rather than a change in composition. (2) The analysis of energy evolution indicates that microwave pretreatment diminishes the total input energy density of the sample, reduces the proportion of elastic energy, and elevates the proportion of dissipated energy. This phenomenon suggests a deterioration in the ore's storage capacity and a transition toward plastic yielding. (3) Dynamic impact tests show that an increase in microwave damage leads to a 45.58% increase in reflected energy, a 16.12% decrease in transmitted energy, and an increase in energy dissipation to 37.49%.

With the increasing complexity of the urban environment and environmental awareness of the public, directional toppling blasting demolition of frame structure buildings often encounters the problems of large collapse recoil distance and strong ground impact vibration, which limits the development and application of blasting demolition technology. To control the collapse recoil and touchdown vibration of the directional blasting demolition of the frame structure building, the design method of the hinge point forward high blasting cutting was put forward, and the theoretical calculation model of blasting cutting height was established based on traditional bottom cutting blasting demolition technology. Meanwhile, a blasting demolition technology of high-cutting blasting with a reserved buffer layer was developed combined with engineering practice. Three kinds of blasting cutting forms were designed to meet the control requirements of different degrees of collapse recoil and touchdown vibration according to the treatment method of the reserved buffer layer. Furthermore, the collapse and disintegration effects of frame structure blasting demolition in different blasting schemes are compared and analyzed by theoretical analysis, numerical simulation, and field test. The results show that the hinge point forward high blasting cutting can increase the inclination angle, prolong closure time, and control the structure's collapse recoil and touchdown vibration, greatly improving the reliability of structural instability and collapse. Compared with the traditional bottom-cutting blasting scheme, the reserved buffer layer hinge point forward high-cutting blasting scheme can effectively shorten the length of the blasting pile, reduce the speed of structural collapse to the ground, and effectively control the height of the blasting pile. The selection of a reserve buffer layer should be considered comprehensively with the structural characteristics of the building and the surrounding environment.

To enhance the mechanical performance of recycled aggregate concrete (RAC) under dynamic loading, this study systematically investigates the synergistic effects of polyvinyl alcohol (PVA) fiber reinforcement and recycled coarse aggregate (RCA) replacement on the dynamic mechanical performance of RAC through split Hopkinson pressure bar (SHPB) impact compression tests. Thirty-six specimen groups with varying PVA fiber dosages (0%, 0.1%, 0.3%) and RCA replacement ratios (30%, 40%, 50%) were designed to elucidate the damage mechanisms and enhancement mechanisms of PVA fiber-reinforced recycled aggregate concrete (PVA-RAC) under impact loading, utilizing comprehensive analyses of dynamic stress-strain curves, failure patterns, and dynamic increase factors (DIF). The results demonstrate that PVA fibers significantly suppress crack propagation via bridging effects, thereby altering the material's failure mode from brittle fragmentation to ductile cracking. Both dynamic peak stress and DIF exhibit substantial improvements with increasing fiber content and strain rate. While higher RCA replacement ratios (40%~50%) diminish compressive strength due to the inherent porosity of RCA, their heterogeneous interfacial properties promote energy dissipation through complex crack propagation paths, thereby partially mitigating strength losses. This study establishes a theoretical framework for the dynamic design and application of PVA-RAC in seismic-resistant protective structures. Furthermore, it pioneers a synergistic approach to integrating construction waste recycling with the development of high-performance recycled building materials. The findings have both theoretical innovation and practical engineering significance.

In order to study the dynamic mechanical response characteristics of crystalline graphite ore under the coupling effect of grade and dynamic load, the dynamic compression tests of crystalline graphite ore samples with four grade levels (5.19%, 10.79%, 12.65%, and 15.50%) under different impact pressures were carried out by using a 50 mm diameter split Hopkinson pressure bar test device. The effects of grade and strain rate on the dynamic mechanical properties and energy consumption characteristics of crystalline graphite ore were comparatively analyzed. Furthermore, a dynamic constitutive model for crystalline graphite ore incorporating both grade and strain rate effects was established based on the viscoelastic ZWT model. The test results show that the dynamic compressive strength and peak strain of crystalline graphite ore increase progressively with rising strain rate, while the elastic modulus remains strain-rate-independent. As the ore grade increases, the initial compaction deformation and peak strain of the samples increase, whereas the dynamic elastic modulus, dynamic compressive strength, and their strain-rate sensitivity gradually decrease. Additionally, within a specific strain rate range, the degree of fragmentation of medium- and low-grade ores intensifies with increasing energy consumption density. In contrast, high-grade ores exhibit minimal variation in fragmentation degree. This indicates that ore grade significantly influences the dynamic fragmentation behavior of crystalline graphite ore. A dynamic constitutive model that considers both grade and strain rate was established, and its accuracy and applicability were verified by comparing the model-predicted results with experimentally obtained dynamic stress-strain curves. The model offers theoretical support for investigating the mechanical behavior of crystalline graphite ore under dynamic loading.

In recent years, the technology of controlled fracture blasting with sequential timing has been extensively utilized in the construction of mining engineering projects and hydraulic infrastructures. To investigate its influence on crack propagation mechanisms in rock masses, C50-grade concrete specimens with 3, 5, and 9 boreholes were cast. Detonators were used instead of explosives to conduct multi-hole blasting tests on rock-like models, examining the propagation paths of cracks and the effects of fracture formation. The LS-DYNA software was used to simulate blasting processes under various working conditions, utilizing the RHT constitutive model to characterize the dynamic failure behavior of rock. A fluid-solid coupling algorithm was employed to simulate the interaction between explosive stress waves and rock masses. By regulating variables such as borehole spacing and detonation timing, several numerical models were developed. Post-processing software was used to extract the simulation results, which were subsequently compared with experimental data to investigate crack propagation patterns within rock masses. The results indicated that time-sequenced controlled blasting technology effectively guides cracks to propagate along predetermined paths. Both the detonation timing sequence and borehole spacing significantly influence crack formation, with more pronounced effects observed in configurations containing a greater number of boreholes. Rational design of initiation timing and borehole spacing can substantially enhance the efficiency of explosive energy utilization while reducing damage to the surrounding rock. This study provides theoretical foundations and technical support for precision blasting operations in complex geological conditions.

The presence of joint fractures significantly influences the dynamic performance of the rock mass. To investigate the effects of joint angles and filling materials on the dynamic response of filling joint samples under impact loading, a series of impact tests were conducted using a split Hopkinson pressure bar (SHPB). Samples with seven different joint angles and three types of filling materials were tested. The relationships between dynamic characteristics, energy dissipation, joint angles, and properties of the filling material were systematically analyzed. The results indicate that: (1) The stress-strain curves of the joint samples of different filling media are significantly different. The stress-strain curves of sediment and lime filling samples show plastic failure characteristics at joint angle ≤45° and brittle failure at joint angle >45°, while gypsum filled samples primarily display brittle failure, except at joint angle =45°, where plastic failure occurs due to stress wave propagation effects. (2) The dynamic compressive strength of joint samples with the same filling material initially decreases and then increases with the increasing joint angle , reaching a minimum value at =45°. Among the three filling materials, gypsum-filled joints exhibit the highest compressive strengths. (3) Energy dissipation characteristics vary with joint angle. The reflected energy ratio increases initially and then decreases, peaking at =45°, while the transmitted and absorbed energy ratios decrease initially and then increase, reaching their lowest values at =45°. These findings provide critical insights into the dynamic behavior of jointed rock masses and have practical implications for engineering applications involving impact or blast loading.

In order to improve the effectiveness of mining roadway blasting excavation and reduce the damage of blasting vibration, the method combined field blasting tests, blasting vibration monitoring tests, and numerical simulation analysis was adopted. The allocation of actual holes and vacant holes was determined according to the utilization rate of the blasting hole. The reasonable delay time was determined based on the peak of particle vibration velocity. At the same time, a numerical model was established based on the size of the roadway and the physical and mechanical properties of both the roadway and the surrounding rock. Based on the material parameters, the impact of roadway blasting excavation on the surrounding rock structure was analyzed using ANSYS/LS-DYNA numerical simulation software. The research findings demonstrate that employing the layout method of central real holes coupled with surrounding empty holes for roadway blasting excavation results in a utilization rate of cut holes exceeding 96%, with the highest utilization rate reaching 97.9%. This indicates that the strategic arrangement of real and empty holes can significantly enhance the efficiency of blasting excavation. Besides, when the delay time increased from 50 ms to 75 ms, the attenuation rate of the peak of particle vibration velocity exceeded 20% at the same position. When the delay time was 100 ms, the peak particle vibration velocity decreased to 2.97 cm/s at 25 m, indicating that the delay time can significantly reduce the damage caused by blasting vibration. Meanwhile, when the layout of central real holes and surrounding empty holes with a delay time of 100 ms was employed to analyze the surrounding rock structure during roadway blasting excavation through numerical simulation, it was observed that a tensile stress of 9.1 MPa was generated at the arch crown position within a 1-meter range from the roadway section. Tensile stress greater than 5 MPa was present at the arch waist position within a range of 1 to 4 m. Therefore, it is recommended to add steel frame support to the arch crown position and spray concrete on the arch waist position.

In mine excavation blasting engineering, smooth blasting typically uses detonating cords to transmit the explosion. This process has low construction efficiency, consumes a significant amount of blasting equipment, and increases the mine's production costs. To solve this problem, the sympathetic characteristics of explosives can be utilized to initiate detonation within holes. A research method that combines experiments on emulsion explosives' sympathetic detonation under various confinement materials with numerical simulations of the sympathetic detonation process in rocks is adopted. By analyzing the impact of confinement conditions, decoupling coefficients, and other factors on the sympathetic detonation distance of explosives, the stable sympathetic detonation distances of emulsion explosives with varying diameters and lengths in boreholes are identified. The conclusions are as follows: confinement conditions significantly influence the sympathetic detonation distance of explosives, with improved confinement resulting in a greater sympathetic detonation range. Under a specific radial uncoupling coefficient, the diameter of the explosive exerts a minor influence on the sympathetic detonation distance, which increases as the charge diameter enlarges. Additionally, the sympathetic detonation distance diminishes with an increase in the radial uncoupling coefficient and extends with the length of the explosive charge. Industrial trials were conducted to verify the findings, with the explosive spacing set at 70 cm. The results indicate that, in comparison to the conventional construction method utilizing detonating cord, the cost of blasting materials for smooth blasting in roof holes was diminished by 33.1 yuan per meter, representing a reduction of 36.1%.

To attain precise regulation of the smooth blasting effects during tunnel excavation, this paper employs the LS-DYNA fluid-solid coupling algorithm and a cubic polynomial ignition and growth equation of state to develop a numerical model of shaped charge jet initiation of explosives. A study on the optimal detonation distance for emulsified explosives within an axially shaped charge configuration was conducted. Additionally, field experiments on axial energy-focused charge structures were performed based on the tunnel blasting excavation project of the Hongshimen Tunnel on the Chengping Expressway (Beijing section). The research results indicate the following: (1) When employing the commonly used axial energy-focused charge structure in industry, approximately 25 cm of movement occurs at the tip of the energy-focused jet 110 s after the main charge detonation. At this point, the jet separates from the plug. Subsequently, the energy-focused jet becomes discontinuous and fragmented during its motion, which may adversely affect the initiation of the explosive charge. Therefore, selecting an appropriate explosive spacing is crucial for the successful detonation of the initiated explosive by the energy-focused jet. (2) Based on the analysis of jet head pressure and explosive reaction characteristics, it is observed that when the explosive spacing exceeds 50 cm, the impact pressure exerted by the jet on the initiated explosive is less than the critical initiation pressure of the emulsified explosive. As the explosive spacing increases, the distance that the jet penetrates the explosive during detonation also gradually increases. When the explosive spacing exceeds 90 cm, the jet fails to initiate the explosive charge. (3) Field tests were conducted based on the tunnel blasting project of the Chengping Expressway (Beijing section) with explosive spacings of 50 cm and 70 cm. The test results revealed that better control of over-excavation and under-excavation was achieved at a spacing of 70 cm. Therefore, under the conditions of this project, a reasonable detonation distance is determined to be 70 cm. The findings of this study can provide valuable references for similar smooth blasting efforts in tunnel engineering.

Differences in thickness, mineral composition, wave impedance, and joint fissures. This often leads to a mismatch between the charge structure of the pre-splitting and cutting holes and the physical and mechanical properties of the layers, which can easily cause the complex rock layers to fail to pre-split. The soft rock layers form chicken-nest-shaped explosive pits due to excessive consumption of explosive energy, making it difficult for pre-splitting and cutting holes to penetrate the entire length of the blast hole effectively. To attain consistent pre-splitting of the composite roof, the LS-DYNA software was employed to analyze the impact of the charging structure on the pre-splitting effect of the composite roof. Based on this foundation, a uniform-dispersion and pressure-holding pre-splitting blasting technique was proposed for the composite roof. Field experiments were conducted, and in conjunction with the preliminary evaluation of the progression of post-blast fractures, the viability of this uniform-dispersion and pressure-holding pre-splitting blasting method was substantiated. The research results indicate that the escape of explosive gas from hard rock layers to soft rock layers is the primary reason for the uneven energy utilization in the pre-cracking explosion of the composite roof. The composite roof uniform dispersion pressure pre-splitting blasting technology divides the pre-splitting holes into multiple chambers according to the layered structure of the composite roof. Each layer has an independent post-explosion pressure holding chamber, which meets the explosive energy requirements of each pre-splitting layer, thereby avoiding excessive consumption of explosive energy in soft rock layers and enhancing the pre-splitting effect in hard rock layers.

Taking the Dengjiashan aggregate mine in Jiangxi Province as the research object, an optimization mechanism and engineering application of air deck charge blasting technology on the powder ore rate was systematically explored in this paper. Firstly, the engineering geological conditions of the mine were analyzed, including the rock mass characteristics and the distribution and development of joints and fissures. This assessment provided a foundation for subsequent blasting test research. Secondly, this research introduced a theoretical framework of air-decking charging and proposed a blasting method utilizing air decks. The mechanism of air-decking charging emphasizes its role in attenuating explosion stress waves, prolonging explosive gas expansion duration, and optimizing energy distribution. Furthermore, this study systematically investigated the influence of different air-decking configurations (top, middle, and bottom placement) on the powder factor. Then, experimental studies and data analysis can validate the method's reliability, culminating in its successful application in field-scale engineering. Thirdly, blasting parameter optimization was carried out using the air deck blasting method based on experimental data, focusing on explosive consumption and inter-hole delay time as key variables. A parameter optimization regression model was subsequently developed (R2=0.8697) to enhance blasting efficiency, demonstrating strong predictive reliability through experimental validation.

To address the challenges of low efficiency, insufficient accuracy, and interference from complex environments in mining blast fragmentation recognition, this paper proposes a novel blast fragmentation recognition method based on binocular vision. By constructing a YOLOv8 instance segmentation model, the post-blast rock contours are accurately extracted under complex lighting conditions. By combining binocular measurement technology with the principles of three-dimensional coordinate transformation and disparity calculation, the maximum size of the fragments is determined. An indoor experimental platform was established to verify the accuracy of fragmentation recognition and size calculation under different parameters. Furthermore, an intelligent recognition architecture for open-pit mine blast fragmentation was proposed, and an automatic fragmentation recognition and analysis system was developed. The results of indoor simulation tests indicate that a lower camera height helps improve the model's recognition accuracy. Although fragment contact slightly affects the recognition of individual targets, the overall accuracy remains unaffected, with the recognition accuracy of all fragments exceeding 85%. The recognition accuracy slightly decreases in dynamic environments. However, the size calculation accuracy for 80% of the fragments remains above 90%, and the overall error remains within an acceptable range, meeting the requirements for real-time monitoring and subsequent analysis in blast fragmentation. This method has been successfully applied at the Husab Mine in Namibia, utilizing Radio Frequency Identification (RFID) technology to obtain material source information. It enables dynamic monitoring, precise analysis, and comprehensive evaluation of the fragment size distribution (FSD) throughout the entire block, providing a novel technological approach for assessing the effectiveness of open-pit bench blasting.

Prestressed continuous rigid-frame bridges, a prevalent structural system in large-span bridge construction, present unique demolition challenges due to spatial constraints and adjacent infrastructure constraints during demolition. This study examined the controlled demolition of a river-crossing, prestressed, continuous, rigid-frame bridge using a blasting demolition practice. The demolition strategy incorporated mechanical crushing of mid-span deck and wing plates, complemented by strategically positioned blasting cuts at critical structural elements, including piers, mid-span box girder webs, top slabs, external prestressed steel cable anchor piers, and bridge-end box girder connections. The implementation of a sequential detonation order (mid-span box girders followed by external prestressed cable anchor piers, concluding with bridge-end connections and piers) resulted in controlled segmental collapse. Numerical simulation using LS-DYNA's dynamic finite element analysis validated the demolition scheme, revealing key process parameters: a total collapse duration of 4.5 seconds and a deck impact velocity of 13.6 m/s. The analysis identified impact stress as the primary mechanism for structural disintegration. A significant finding emerged regarding external prestressing technology. While originally implemented to enhance service performance and load-bearing capacity, the release of prestressing forces through controlled blasting was found to improve structural fragmentation efficiency significantly. Field implementation demonstrated the technical feasibility and safety of this approach, providing an effective solution for dismantling long-span, prestressed, continuous, rigid-frame bridges in complex environments. The study establishes a comprehensive framework for similar demolition projects, highlighting the importance of integrated mechanical and explosive techniques in modern bridge demolition engineering.

In the reconstruction and expansion projects of expressways, a large number of cross-line bridges cannot meet the development needs of modern transportation and are facing demolition and reconstruction. Traditional manual and mechanical demolition methods have drawbacks, including low efficiency, prolonged timelines, and substantial traffic interference. In contrast, blasting demolition-with its inherent benefits of safety, economic viability, and operational efficiency has emerged as the optimal technique for dismantling cross-line bridges on expressways. Based on the reconstruction and expansion project of the section from the Hubei-Henan boundary to Junshan on the Beijing-Hong Kong-Macao Expressway, one-time combined blasting demolition was carried out on five cross-line bridges in the K1018+990~K1048+550 section. Through the quantitative design, fine construction, and multidimensional protection of four types of bridges-such as equal-section catenary hingeless arch bridges, inclined-leg rigid frame bridges, half-through arch bridges, and steel frame arch bridges-the goal of safe and efficient blasting demolition was realized. The practical results show that the collapse mode and disintegration effect of the bridge can be effectively controlled by reasonably designing the blasting cut and initiation sequence. The distributed cooperative detonation system, based on radio communication, overcomes the spatiotemporal coordination problem of synchronously detonating group bridges over a long interval. The protection measures of ‘covered protection+near body protection’ were adopted to control the splash of individual flying debris effectively. The ‘rigid support layer+elastic buffer layer’ protection system effectively prevents the impact damage of the bridge collapse on the high-speed pavement. The engineering practices presented herein demonstrate that through meticulous design, synchronized control strategies, and multi-tiered protective measures, the safe and efficient demolition of cross-line bridge groups across extensive expressway sections in complex environments can be accomplished.

This study investigates the blasting demolition of a 180 m-high reinforced concrete chimney under site-specific conditions, systematically addressing critical challenges in collapse control through targeted engineering solutions. By designing symmetrically arranged directional and positioning windows, combined with empirical formula calculations, optimal blasting parameters were determined to be a 216 central angle and a 3.5 m cut height, effectively guiding the chimney's collapse along the predetermined trajectory without significant backward displacement. A 1:1 scale numerical model employing the Interface Stress Element Method was developed to simulate the collapse process, showing complete structural failure within 14.0 seconds with controlled lateral deviation (<0.5%) and minimal settlement/forward surge. A comparative analysis with the Decoupled Co-node Model revealed the superior performance of the Interface Stress Element Method in simulating rebar-concrete decoupling at cut closures, reducing backward displacement by approximately 1.0 m through differentiated load-bearing mechanisms at material component nodes. The model successfully replicated restrained rebar scattering during top section ground impact, due to the bonding forces of the spring elements, confirming enhanced simulation accuracy in collapse kinematics. Field implementation validated the numerical predictions, achieving precise directional collapse, complete structural disintegration, and compliance with safety thresholds, thereby establishing a replicable framework for ultra-high chimney demolition engineering.

This study introduces a straightforward two-dimensional vortex model to examine the release and absorption of vortex energy. The energy transfer resulting from vortex collapse during explosive detonation and the microscopic mechanisms underlying detonation growth are analyzed. The relationship between the macroscopic phenomena of detonation growth and extinction and microscopic factors, such as pore size distribution, is established through experimental validation. Findings suggest that the stability of the detonation process is microscopically governed by thermal flux and the effective number of vortices per unit volume within the field. The effects of particle size and density of the explosives on the macroscopic detonation behavior can be elucidated by considering the effective vortex volume concentration and distribution. Control of the ignition vortex pore size is essential, and stabilization of detonation can be achieved by adjusting pore sizes within defined minimum and maximum limits. An optimal and effective pore volume concentration is necessary to maximize the energy utilization efficiency of the explosives. Based on this research, successful tests on the regulation of detonation velocity of emulsion explosives through the use of mixture sensitizers with varied size distributions and constant densities were conducted.

Accurate and efficient explosive detection technologies facilitate real-time monitoring of blasting materials throughout their storage, transportation, and usage, enabling the prompt identification of expired or unstable explosives. Furthermore, trace detection methods can detect residues of illegal explosives, offering technical support for safety supervision and public security, while striking a balance between engineering efficiency and environmental safety. This study introduces an optical fiber Raman sensor utilizing silver nanoclusters (AgNCs) for the explosive detection of explosives. By integrating Raman spectroscopy with fiber-optic sensing technology, it achieves highly sensitive spectral detection and efficient signal transmission specifically for TNT detection. The AgNCs substrate, modified with silver-sulfur bonds and functionalized with 4-ATP, acts as a capture probe for TNT. The formation of the TNT-4-ATP complex significantly amplifies the SERS signal of TNT, resulting in a detection limit (LOD) as low as 10-10 M.

A study was conducted using explosive cutting cords to titanium alloy plates to quantitatively investigate the additional kinetic energy generated during blade fracture in aviation engine case inclusion experiments. The additional kinetic energy was analyzed through both computational and experimental approaches. Using AUTODYN software, two computational methods were employed: the center-of-mass motion method (yielding E1) and the particle-by-particle accumulation method (yielding E2). The accuracy of these methods was systematically compared. Experimental validation was achieved by measuring the additional kinetic energy (E3) in controlled explosion experiments. The computational results were verified against experimental data, confirming the reliability of both the simulation and testing methodologies. The study reveals that the maximum additional kinetic energy generated during the severance of titanium alloy plates constitutes a smaller proportion of the total kinetic energy proportion than the threshold proposed by the FAA company. These findings provide critical insights for designing and evaluating cartridge inclusion experiments in aviation safety applications.

This paper aims to explore the development of a risk management system for engineering blasting to achieve systematic management of quality, safety, environmental, and occupational health risks throughout the entire life cycle, encompassing all aspects and elements of blasting activities. Based on the establishment of comprehensive safety and environmental awareness, it advocates the use of systems engineering methodology to analyze risks in the field of engineering blasting in depth. The article follows the internationally accepted ISO 9001(Quality Management System), ISO 45001(Occupational Health and Safety Management System), and ISO 14001(Environmental Management System) standards, and constructs a scientific risk management framework. It is proposed to combine technical means, such as standards, metrology, inspection and testing, certification, and accreditation, with a risk management model for engineering blasting systems based on the PDCA (PLAN-DO-CHECK-ACT) cycle. This model emphasizes prevention as its primary focus, and through improvement, it ensures that risks are within a controllable range. The article further introduces digital twin technology, and constructs the engineering blasting B-NQI (B-NQI risk-based digital integration of engineering blasting quality, safety, environment and occupational health) system, which realizes real-time monitoring, prediction, control and decision of risk information, greatly improving the efficiency and accuracy of risk management of engineering blasting system. The research not only enriches the theoretical framework of engineering blasting risk management but also provides practical tools and methods for industry applications. Constructing the B-NQI system helps reduce various risks in the engineering blasting process, ensures project progress, and provides strong protection for worker safety and environmental protection.

To investigate the inhibitory effect of calcium carbonate on methane explosion in the presence of coal dust, experiments and numerical simulations were applied in this study. The inhibitory performance of calcium carbonate under various particle sizes and concentrations was analyzed, providing a theoretical basis for safety protection in high-risk environments, such as coal mines. By using a self-developed 9.6-meter-square straight pipe, the experiments were conducted with Calcium carbonate, whose particle sizes ranged from 6.5 to 74 micrometers, and the concentration levels were maintained within the optimal range of 100 to 200 g/m3. Based on this, the optimal particle size and concentration of calcium carbonate were determined by analyzing the pressure changes during the explosion process. The experimental findings reveal that the explosion process can be divided into four stages: initial methane combustion, subsequent methane combustion involving coal dust, calcium carbonate decomposition, and a final inhibition stage. Meanwhile, the calcium carbonate reduces oxygen concentration. It absorbs heat through thermal decomposition reactions, which slows down the combustion reaction rate and establishes local thermal equilibrium, thereby suppressing the propagation of the explosion. The calcium carbonate achieves optimal explosion suppression performance with a maximum pressure reduction rate of 46.7% at specific parameters: a calcium carbonate of 150 g/m3 combined with a particle size of 23 micrometers. Additionally, numerical simulations were employed to verify the experimental results, which demonstrate that the pressure change trends are consistent with the experimental results, with a relative error of less than 15%. As an effective explosion inhibitor, calcium carbonate demonstrates significant inhibitory effects on methane explosions in the presence of coal dust under specific particle size and concentration conditions. This study provides experimental and theoretical support for the application of calcium carbonate in industrial explosion protection.

The study aims to investigate the explosion characteristics of methane/air premixed gas across various temperatures and ignition positions. Under winter and summer conditions, respectively, using a custom-designed methane/air premixed gas explosion test apparatus, tests are conducted with different aspect ratios for a variety of concentrations of methane/air premixed gas explosion test, systematically analyzes the influence of temperature, aspect ratio, and concentration of the premixed gas explosion on the overpressure peak and impulse characteristics of explosions. Furthermore, by utilizing magnitude analysis methods and data fitting techniques, the study identifies the primary factors influencing these overpressure peak and impulse characteristics, and proposes a corresponding approach. In conjunction with the process of magnitude analysis and data fitting, the main factors affecting the overpressure peak and impulse characteristics were systematically analyzed, leading to the development of prediction formulas for the overpressure peak and impulse of methane/air premixed gases. The results indicate that: (1) the trends of peak overpressure and impulse in relation to increasing L/D ratio are generally similar for a specific gas concentration. However, these trends differ between winter and summer temperatures. Specifically, at a gas concentration of 7.5%, both peak overpressure and impulse initially decreased, then increased, and subsequently decreased again under winter temperature conditions, while they continued to decline under summer temperatures. For gas concentrations of 9.5%, 11.5%, and 13.5%, both peak overpressure and impulse consistently showed a decline in both winter and summer temperature conditions. (2) The relationship equations for peak overpressure and impulse, concerning the L/D ratio and methane/air premixed concentration, were established using magnitude analysis and data fitting under winter temperature conditions. The theoretical data were compared with the experimental results to verify that the errors were within 15%. The overall data match well, which verifies its reliability, and can express the decay law of overpressure and impulse with the L/D ratio and gas concentration more intuitively, thereby facilitating the rapid prediction of overpressure peaks and impulses.

The design of the tunnel blasting course is an important comprehensive practical teaching link of the "Blasting Engineering" course of related majors in colleges and universities. To explore new ideas for reforming teaching practice, given the challenges of complex calculations, difficult parameter selection, and cumbersome diagram drawing in traditional curriculum design, a tunnel blasting intelligent design software platform was proposed for course design. By integrating digital and intelligent design technologies, the authors develop an intelligent design platform that converts abstract blasting parameter design into a clear visual model. The platform includes four modules: blasting design, resource library, data management, and global settings. It innovatively realizes real-time modification of blasting parameters and implementability judgment, has a guided operation process, and forms an interactive teaching mode. The practical results demonstrate that the intelligent design platform effectively reduces the computational burden and the subjectivity of parameter selection for students in traditional teaching practices through the guided operation process, enhances drawing efficiency and accuracy, and ensures that the blasting design scheme is scientifically and reasonably formulated. The interactive teaching mode enhances students' ability to combine theory and practice, stimulates their interest in active learning, thereby improving their understanding of professional knowledge, cultivating intelligent design ideas, and providing support for becoming high-quality talents serving the new era.