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 (R²=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.

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.

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.

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.

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.

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%.

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.

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.

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.

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.