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.

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.

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%.

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 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.

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.

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 α≤45° and brittle failure at joint angle α>45°, while gypsum filled samples primarily display brittle failure, except at joint angle α=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 α, reaching a minimum value at α=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 α=45°, while the transmitted and absorbed energy ratios decrease initially and then increase, reaching their lowest values at α=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 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%.

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 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.