In order to study the protective performance of minesweeper protective equipment on the chest and abdomen under the action of explosion shock wave, it is necessary to explore efficient test methods to improve the experimental research index system and overall performance of individual soldier protective equipment. In this paper, two sets of minesweeper protective equipment were taken as experimental research objects, and the real explosion test of minesweeper EOD operators for typical kneeling posture was designed based on Hybird III dummy model under different sealing conditions. The shock wave was generated by the explosion of 50 g TNT charge column. Two wall overpressure sensors were installed in the chest and abdomen of the dummy model to measure the shock wave overpressure generated by four real explosion tests, and a free field pressure sensor was set at the same distance relative to the explosion source to compare the test data. Using the dummy data acquisition system, the whole process data of overpressure on the chest and abdomen after the shock wave penetration of the minesweeper protective equipment were obtained. Through data processing, the pressure-time curve of chest and abdomen subjected to explosion impact and the peak attenuation rate of overpressure were obtained and compared. The test results preliminarily verify that the better the sealing performance of the joint, the higher the protection performance, which indicates that the protective equipment with high sealing performance has a certain blocking attenuation effect on the diffraction of explosion shock wave, and can reduce the damage caused by superimposed overpressure to the chest and abdomen to a certain extent. The experimental design and data analysis in this paper can be used for further equipment performance improvement.

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

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

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

Abstract: This study aims to address the challenge of rapid tunnel excavation without the use of explosive. A new oxygen expansion rock breaking technology suitable for general tunnel excavation such as cutting, expanding, auxiliary and peripheral holes is explored, researched, and summarized. The drilling and blasting parameters optimized for tunnel excavation are also provided in detail. The experimental study section consists of granite with a compressive strength ranging from 90 to 100 MPa, developed cleavage cracks, and average blastability. Through field tests and continuous improvement, an average cycle footage of 2.5 m per two-day cycle is achieved for a tunnel area of approximately 65 m², meeting the requirements for rapid excavation when explosives cannot be used. The research demonstrates that the new gas expansion rock-breaking technology can effectively excavate tunnels in hard rock masses. It offers advantages such as safe operation, high efficiency in rock breaking, no involvement with civil explosives or dangerous chemicals used in explosive production, absence of explosion shock waves and low vibration amplitude. This technology provides a solution to situations where civil explosives are prohibited due to complex environmental conditions or slow progress using mechanical methods.

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

Smooth blasting is the main method for controlling excavations in hard rock tunnels, but due to the complex mechanism and process of rock fragmentation by blasting, as well as the rough design of blast parameters, it is difficult to achieve a smooth excavation profile for the entire tunnel. This study focuses on the Level Ⅲ hard rock section of the Zhaishan tunnel, and through a large number of blasting tests and investigations, it was found that there were problems such as over-excavation and under-excavation, misfire, and secondary blasting construction around the tunnel profile after the original blasting plan was carried out. Based on relevant specifications and engineering experience, optimization measures were proposed for the blasting parameters, including reducing the spacing between contour holes, increasing the number of relief holes, using water bag as the charge decking and stemming, as well as reducing the amount of explosives loaded in each hole. The results showed that the optimization measures can improve the utilization of explosive energy, achieve uniform fragmentation of the rock mass, and control over-excavation and under-excavation of the tunnel perimeter rock mass. The blast parameter optimization also results in smooth and round tunnel profile with clear blast hole marks, which helps to improve the quality of excavation and accelerate the progress of tunnel construction.

The conclusions including: the Kuznetsov and kansake models are still applicable to the prediction of unit explosive consumption in bench blasting tunnel engineering, and the Kuznetsov model considers the influence of rock mass characteristics, which is more practical than the kansake model. In addition, the Kuznetsov model can predict the average blasting fragment as the basis of the distribution model of blasting fragment. Compared with the lower bench, the upper bench has higher single blasting consumption, higher content of fine particles and smaller fragments. The Kuz-Ram model has a good prediction effect for the small blasting fragments that below the average value. For the large blasting fragments that above the average value, the KCO model has a better prediction effect, and it has more accurate for the prediction of the largest blasting fragment. This paper analyzes the applicable conditions and scope of the prediction model for rock fragment, which provides a basis for the unit explosive consumption and fragment distribution of tunnel blasting. The methods for predicting the specific consumption of explosives and the fragmentation of rock mass during blasting originated from open-pit blasting. However, the stress state of the rock mass in stepped tunnels is different from that in open-pit mines, so it is unknown whether the above prediction methods are applicable to stepped tunnel blasting. Based on statistical data from the bench blasting in the Tianjiangli tunnel, several commonly used calculation methods in open-pit mines were used to predict the specific consumption of explosives and the distribution of fragments, and the predicted results were compared with the actual measurements. The results show that the Kuznetsov model and the Kansake model are still applicable to predicting the specific consumption of explosives in stepped tunnel blasting, and the Kuznetsov model takes into account the influence of rock mass characteristics, making it more practical than the Kansake model. In addition, the Kuznetsov model can predict the average value of the blasting fragmentation and serve as a basis for the fragmentation distribution model. The specific consumption of explosives is higher on the upper bench, resulting in a higher content of fine particles and smaller overall rock mass after blasting, while the specific consumption is lower on the lower step, resulting in a lower content of fine particles and a larger overall rock mass after blasting. The Kuz-Ram model is better in predicting the blasting fragmentation of small rock masses with a block size below the average value, while the KCO model is better for predicting the blasting fragmentation of large rock masses with a block size above the average value, and the KCO model can accurately predict the maximum blasting block. This article analyzes the applicable conditions and scope of the prediction models and provides a basis for the specific consumption and fragmentation distribution in tunnel blasting.

In open-pit bench blasting, blasting TBlasting toe rocks is an important indicator to measure the blasting effect in open-pit bench blasting, and it is most directly influenced by the blasting parameters have the most direct influence on the formation of blasting toes. In order to find outresearch the influence of ultra-deepsubdrilling on the smoothness flatness of bench in deep-hole bench blasting, statistical analysis of the relationship between damage variables and wave velocity in rock mass was conducted based on the basic theories of rock damage mechanics. based on the basic theories of rock damage mechanics and through statistical analysis of the relationship between damage variables in engineering and wave velocity in rocks, Tthe threshold values of damage variable, D_d for critical damage variable damage state of of rock mass is determined as Dd that is was 0.2, and the damage threshold D_t of for rock breaking mass in critical broken state is was were defined as 0.2 and 0.8, respectively. based on the basic theories of rock damage mechanics and through statistical analysis of the relationship between damage variables in engineering and wave velocity in rocks. Furthermore, Based on the dynamic damage model of rock with comprehensive consideration of the damage effect of tension and compression, the damage range of bench blasting under different conditions of with different subdrilling conditionsultra-deep was simulated by using the dynamic finite element analysis program LS-DYNA based on the dynamic damage model of rock mass with a comprehensive consideration of tension and compression effect. Meanwhile; based on the threshold of critical damage variable, the fluctuations distribution image of the bench surface after blasting was drawn to determine the optimal ultra-deep of subdrilling hole based on D_t the threshold of critical damage variable, and the image is was used for the quantitative analysis, so as to ensure that the rock mass of upper bench was fully damaged without affecting the construction of the lower bench surface. Finally, combined with the actual situation of deep-hole bench blasting in Ezhou Airport, the influence mechanism of ultra-deepsubdrilling on blasting toes is was verified in the deep-hole bench blasting of Ezhou Airport, and an optimal method for determining the optimal ultra-deepsubdrilling value for deep-hole bench blasting is was concluded.

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.