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.

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.

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.

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 μs 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.

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.

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.

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%.

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.

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.

To further investigate the influence of surrounding rock mass damage on the rock burst mechanism, material selection for simulating the damage zone was carried out, and a test piece containing the damage zone (1000 mm×600 mm×400 mm) was fabricated. Using the self-developed rock burst model test system's drilling device, caverns were excavated in the specimens (with a hole diameter of 110 mm). Rock burst model tests were then conducted on specimens with varying damage zone thickness through step loading, considering the damage effects on the surrounding rock. During the tests, cameras monitored the damage process of the tunnel wall. Image expansion was performed based on the rubber paper model principle, and the box dimension of the expanded image was calculated and analyzed. The results show that the macro-failure process of a rock burst consists of crack initiation, particle ejection, crack propagation, and debris avalanche stages. As the thickness of the damage zone increases, the failure depth of the specimen chamber's side wall gradually increases. In the stage of slow increase and sharp increase in the box dimension of the left and right tunnel walls, the growth rate of the box dimension decreases linearly with the increasing thickness of the damage zone. With the increase in damaged zone thickness, cracks in the tunnel wall primarily concentrate within the damaged zone during loading, and the damage depth of the tunnel wall increases when the cavity is damaged. The findings further elucidate the breeding and failure mechanism of rock bursts in deep-buried caverns under the condition of surrounding rock damage.