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.

Safety management plays a vital role in blasting operations, and blasting safety is closely related to the processes of drilling, blasting, loading, transportation, and dumping, with significant interactions among these procedures. However, due to the diverse sources and complex structure of current blasting safety data, the lack of systematic integration poses challenges for on-site personnel to accurately acquire critical safety knowledge under complex working conditions. To address this issue, this study applies a BERT-BiLSTM-CRF-based method for entity recognition in the field of blasting safety management. The BERT pre-trained model is first used to obtain dynamic word embeddings, followed by optimal label sequence tagging using the BiLSTM-CRF model. A knowledge graph covering seven entity types and nine relationship types is constructed and stored using the open-source Neo4j graph database system. Experimental results show that the F₁-score for all entity types exceeds 60%, demonstrating that the proposed model significantly improves entity recognition accuracy compared to traditional models. Based on this, a knowledge graph-based Q&A system for blasting process safety management in open-pit coal mines is developed, enabling rapid querying of domain knowledge and efficient matching of various blasting processes with safety standards. With the support of this Q&A system, on-site engineers can make timely and informed decisions in complex blasting safety management scenarios.

Blasting Engineering is a core course in urban underground engineering and mining engineering in universities, and teaching blasting experiments is an indispensable link in practical teaching. As explosive engineering has a characteristic of great danger, the traditional explosive engineering experiment construction is rugged enough to be carried out indoors, which inconveniences teaching. Therefore, more and more schools rely on virtual simulation platforms. According to the teaching idea and demand of explosive engineering virtual simulation, this paper builds a virtual simulation teaching platform for blasting experiment teaching. Unity3D, a development tool for virtual simulation systems, was utilized to ensure high compatibility when running on different platforms. Meanwhile, the 3DS Max and Maya were applied to build and improve a realistic model. Furthermore, problems like slow loading speed and non-realistic animation through the cloud rendering technology were solved. The software ANSYS was used to simulate the propagation mechanism of blasting vibration waves in different rock layers better to reflect the blasting vibration waves in practical engineering. Finally, the wave field cloud map was saved as a snapshot in the virtual simulation system, and virtual simulation experiments of blasting vibration were carried out. The practice and application results show that the virtual simulation experiment platform can enable students to participate in the experiments of explosive engineering independently and deeply and improve students' experimental experience and practical innovation ability.

To investigate the fracture toughness of natural slate under dynamic loading, dynamic impact tests were conducted on notched semi-circular bending slate specimens by a 50 mm diameter split Hopkinson pressure bar testing system and the crack growth process was recorded by the high-speed cameras. Furthermore, the dynamic fracture toughness and crack propagation rate of slate under different impact pressure and prefabricated crack lengths were studied. The results show that the dynamic fracture toughness of the specimen is positively correlated with the impact pressure and loading rate, and the dynamic fracture toughness first increases and then decreases with the rise of the prefabricated crack length. According to the fitting results, the dynamic fracture toughness of the specimen reaches the maximum value when the prefab crack length is 7.45 mm. The maximum values of dynamic fracture toughness at 0.2, 0.3 and 0.4 MPa were 2.99, 3.57 and 4.14 GPa·m^1/2, respectively. The failure process of the specimen can be divided into five stages: dynamic damage, crack propagation, crack formation, crack propagation, and specimen fracture. The propagation speed of the main crack of the specimen greatly fluctuates, while the prefabricated crack length has little effect on the propagation velocity of the specimen. The study revealed the differences in dynamic fracture behavior of slate specimens under different working conditions.

Drilling and blasting is still the most efficient way to explore deep phosphate mine excavation and mining. There is a severe constraint on the efficiency of phosphate mine digging as its level remained at 70 to 80 meters every month for many years. Therefore, the ore rock blastability classification is critical for the deep phosphate mine working face. The longitudinal wave velocity tests of the rock body in an underground phosphate mine in Yichang, Hubei Province, and measurements of physical and mechanical properties such as rock density, uniaxial compressive strength and tensile strength were carried out. The rock density, uniaxial compressive strength, tensile strength, and rock integrity coefficient were obtained for four types of rocks, namely, dolomitic striped phosphorite, dense striped phosphorite, argillaceous striped phosphorite, and carbon-bearing argillaceous dolomite. To complete the deep phosphorite workings of the mine rock blastability classification, a BP neural network model was established by stochastic functions to generate a large number of learning and testing samples using the Matlab neural network toolbox as taking the pre-measured rock density, uniaxial compressive strength, tensile strength and rock integrity coefficients as inputs and the rock blastability classification as outputs. The grading results show that dolomite-banded phosphorite and mud-banded phosphorite are moderately blastable, and dense-banded phosphorite and carbonaceous mud dolomite are difficult to blast. According to the classification results, the blasting parameters of the stope can be optimized to enhance the blasting effect, reduce the single consumption and the bulk rate of explosives, and improve the safety and economic benefits of deep phosphate mining.

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.

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.

Taking the construction of Shikui Road Station to Labor Park Station of Dalian Metro Line 5 as the background, a delicate blasting design was used to control the influence of interval tunnel construction on adjacent buildings. In order to prevent the risk of settlement of adjacent bridge piles, a deep hole pre-reinforcement method of non-shrinkage double-liquid grouting (WSS) was used on the tunnel face. The blasting parameters of the tunnel face were optimized, and a detailed blasting design was given by combining with the step sequence of the tunnel construction method (step method and CRD method). The right line utilized the step method, while the left employed the CRD method. The upper bench of the step method and the upper left chamber 1 of the CRD method were blasted twice: initial cutting blasting to create an empty surface followed by secondary blasting to reduce vibration. The unit consumption of explosives in the cutting part was 1.87~2.33 kg/m³ and 0.40~0.80 kg/m³ in other sections, with the Ms-15 nonel detonator used for maximum section control. In addition, the blasting vibration attenuation law formula was inverted through blasting vibration monitoring, facilitating a pre-check for safety. Furthermore, a numerical simulation using the SPH method was conducted for cutting blasting near side-piercing bridge piles with a single-stage charge of 0.30 kg. The response of the bridge pile located 5 m from the detonation point and subjected to explosive load was analyzed. The blasting operation in this area had been completed, and the piers were safe and sound, indicating that the construction scheme for the side-crossing bridge pile section was feasible. Additionally, the stress wave propagation in strata and bridge piles was simulated, showing speeds of 3280 to 3590 meters per second in bridge piles, and an average speed of 1620 meters per second in rock and soil layers. The propagation speed in bridge piles was significantly higher than in the weathered and clay layers. The SPH method proved effective for large-scale particle calculations without requiring supercomputing power for explosives and adjacent rocks.