During aero-engine casing containment tests, the explosive separation method used to achieve the constant-speed fly-off of titanium alloy blades often produces a bright titanium fire phenomenon. This titanium fire obstructs high-speed camera recording of the blade fly-off process. To address this issue, this study analyzed the mechanism of titanium fire generation and proposed a barrier layer method to suppress titanium fire during shaped energy cutting of titanium alloys. Numerical simulations using the Euler algorithm in AUTODYN were conducted to evaluate the blocking effect of the barrier layer and its feasibility for titanium fire suppression. Experimental investigations were then performed to quantitatively assess the brightness reduction of titanium fire, comparing the effectiveness of four barrier materials. The results indicate that 0.1mm thick aluminum and titanium tin foil achieve titanium fire suppression rates of 29.5% and 24%, respectively, demonstrating moderate effectiveness. A 0.1 mm thick copper sheet shows poor performance with a suppression rate of only 4.3%, while a 0.1 mm thick aluminum silicate coating exhibits the best performance, achieving a suppression rate of 70.9%. This study has summarized the mechanism of titanium fire suppression suing barrier layers during shaped energy cutting of titanium alloy plates and validated the feasibility of the barrier layer method. The findings can provide a practical approach for titanium fire elimination in explosion separation processes involving shaped energy cutting of titanium alloys.

Given the current lack of comprehensive research on the mechanism of rock fracturing by high-pressure gas, this study draws upon the research method used to determine peak pressure at the borehole wall in the drilling and blasting method. By analyzing the complete rock fracturing process through the liquid oxygen expansion method, a calculation model for the peak pressure at the borehole wall was derived from the shock tube theory, considering the changes in the rock medium and uncoupling coefficient. Using a dynamic strain tester, a concrete model experiment was conducted to measure the peak pressure at the borehole. Under fixed conditions of a 60 mm expansion tube diameter and four different apertures (75~120 mm), the peak pressure was measured. The test results show that, with the same liquid oxygen equivalent and rock medium conditions, the time to peak pressure increases linearly with the uncoupling coefficient, following the relationship t=230.6k-127.85. As the uncoupling coefficient increases, the peak pressure at the borehole wall decreases gradually, with the attenuation rate gradually slowing. A comparison between the experimental results with the theoretical calculations shows a similar trend in peak pressure attenuation with the uncoupling coefficient, confirming the reliability of the theoretical model.

To investigate the energy evolution and failure patterns of magnetite during blasting and to minimize the impact of blasting disturbances on the stability of pillars and surrounding rocks, a series of multi-stage strength impact tests were conducted on magnetite samples using a Split Hopkinson pressure bar (SHPB) apparatus. The dynamic response characteristics of magnetite were analyzed, focusing on parameters such as dynamic peak compressive strength, failure modes, fragmentation size, and energy dissipation density under varying strain rates. The results show that magnetite's dynamic peak compressive strength and energy dissipation density increase exponentially with the increase in strain rate. At the same time, the crushing size decreases exponentially, demonstrating a strong strain-rate dependency. The failure process of magnetite can be divided into three stages: crack compaction, elastic deformation, and crushing. The dynamic increase factor (DIF) also increases with the increase in strain rate. The failure mode of magnetite transitions from splitting failure at lower strain rates to crushing failure at higher strain rates as crack interactions intensify. Therefore, when blasting rock breaking is applied to magnetite mining, it is crucial to balance impact strength and energy dissipation to enhance crushing efficiency while meeting the required fragmentation standards.

To enhance excavation speed in small-section tunnels and address the limitations of oblique and burn cut blasting techniques, a new burn cut blasting method combining long and short straight holes is proposed based on rock blasting theory, stress wave rock breaking theory, and sacrificial blasting theory. This method improves the burn cut blasting approach with equal resistance lines, eliminating the need for empty holes. The blasting parameters and cavity formation process are discussed in detail. Through field tests and the use of different detonators and cutting layouts, the performance of various cutting methods was evaluated in terms of blasting advance, powder factor, and over-excavation and under-excavation. The results show that the proposed burn cut blasting method is not constrained by tunnel cross-sectional area, allowing for independent hole depth design and optimal delay intervals to achieve staged and layered blasting. This technique enhances the role of free surfaces in the cutting process, reducing the minimal resistance line in deep holes. The resulted cavity is a regular rectangular shape, increasing blast hole utilization from 78.5% to 89.3%. Field tests show that, in small-section tunnel blasting, this method increases the advance from 1.6~2.2 m to 2.2~2.5 m compared to traditional inclined-hole cut blasting. Over-excavation was further reduced by 20%~30% when the displacement of surrounding holes remained within 10cm. The proposed cutting method effectively controls costs, improves operational efficiency, and offers both technical and economic advantages with improved blasting outcomes.

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 mitigate blasting vibration during the excavation of a drainage tunnel located 2.30~3.10 m beneath an existing tunnel, an optimized blasting scheme using millisecond blasting by electronic detonators and a subsection in blasting holes was implemented. The field blasting scheme was initially adjusted based on the conventional blasting situation near the existing tunnel. This involved optimizing hole position parameters and reducing the number of holes. Before the formal blasting in the underpass section, a single-hole blasting test was then conducted near the excavation face to capture the vibration waveform and geological information. Using the linear superposition method, the vibration waveform of various delay intervals was analyzed to select the optimal delay interval. To further improve blasting performance and reduce the vibration of the cut blasting, the first blasting in the cut area was performed by using the subsection blasting in the hole. Field tests and calculations determined that the optimal delay times were 5 ms for the same row of cut holes or spreader holes, 40 ms between rows, and 3 ms for contour holes. The new blasting scheme was implemented and optimized in the field. When the drainage tunnel was excavated at a footage of 1.5 m through the existing tunnel, the maximum vibration of the road surface monitoring point at a distance of 3.10 m directly above was maintained below 4.0 cm/s, ensuring structure safety. Using electronic detonators for precise initiation and sectional blasting successfully controlled site vibration, protected adjacent structures, and provided valuable insights for similar future projects.

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.

In blasting demolition projects of housing buildings, reinforced concrete columns serve as the primary load-bearing structural elements and consequently represent the most frequently targeted components for controlled demolition. The effectiveness of reinforced concrete column demolition through blasting operations plays a pivotal role in ensuring structural instability and controlling the overall collapse mechanism. The evolution of modern reinforced concrete columns, characterized by increased cross-sectional dimensions, higher reinforcement densities, and enhanced material strengths, has significantly elevated the technical complexity of the design of blasting parameters and the protection of flying rocks. The Particle Blasting Method coupled with the Finite Element Method (PBM-FEM) was employed to simulate the dynamic process of explosion impact loading and explosion gas escaping from the borehole through the high-speed motion collision of particles. Full-scale 1∶1 physical model tests were conducted using industrial electronic detonators to accurately replicate the blasting demolition process of high-rise building structural members. The research reveals critical insights into the failure mechanisms and damage propagation characteristics of reinforced concrete columns under controlled demolition conditions. The results show that the explosion gas escapes from the orifice and reduces the utilization rate of explosive energy due to the limited constraint effect of the blocking material on the side of the blast hole. The severity of concrete spalling on the surface of the column is left and right sides > front side > back side. The direction of the minimum resistance line is the main direction to induce concrete damage and throwing.

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.

Blasting excavation generates transient P-waves that significantly impact tunnel stability. For water-filled diversion tunnels, the dynamic response of the surrounding rock differs from conventional dry tunnels. Most existing analytical studies focus on the steady-state solution and single-lined tunnels, rarely accounting for composite linings or the presence of water. This paper investigates the transient stability response of deep-buried circular composite lining diversion tunnels under transient P-wave disturbances. The fluid within the tunnel is treated as a distinct medium, and the tunnel-lining interface is considered a non-ideal contact surface. By applying Fourier synthesis, wave function expansion, and trapezoidal quadrature formula, an analytical solution is derived. Validation through comparison with existing literature demonstrates the method's effectiveness. The study analyzes the effects of Poisson's ratio of surrounding rock, the non-ideal interface's elastic coefficient, and the disturbance's loading duration on the dynamic stress concentration coefficient. Results indicate that the compressive stress concentrations occur at the roof and floor, while tensile counterpart concentrations appear at the two sidewalls during dynamic disturbance. As Poisson's ratio increases, there is a transition from tensile to compressive stress concentration, with a gradual degree in compressive stress intensity. Poor contact between the rock mass and liner induces oscillations in the stress time-history curve. The dynamic response converges accordingly as the elastic coefficients of an imperfect interface approach those of a perfect interface. With increasing blasting load duration, peak dynamic stress around the roof and floor initially rises, then stabilizes, while stress at the sidewalls initially decreases before leveling off.