As rock-breaking technology advances, the limitations of traditional explosive methods are increasingly evident. The liquid oxygen energy storage method, a new non-explosive technique, presents an uncertain blasting mechanism and scientific challenges that must be addressed. Field vibration tests were conducted to analyze the variation trends and the decay characteristics of peak vibration velocities in particles to further characterize the liquid oxygen energy storage rock-breaking blasts and address the challenges of applying empirical methods on-site. Additionally, indoor small-scale blasting experiments were performed to identify key parameters for small liquid oxygen charges. The experimental results reveal that the liquid oxygen energy storage effectively fractures rocks while maintaining low dust and noise levels. Peak particle vibration velocities at 3 m, 6 m, and 10 m under single blast conditions were 3.04, 1.24, and 0.62 cm/s, respectively. The small-scale charge tests reveal that for the liquid oxygen charge to detonate successfully and effectively fracture the rock, appropriate inflation time and pressure are required to prevent detonation and other issues. Increased inflation time and pressure lead to more significant adsorption of liquid oxygen by the charge's absorbent, facilitating saturation and enhancing detonation probability. Overall, the liquid oxygen energy storage method stands out due to its low vibration, environmental friendliness, and non-polluting nature, marking a significant potential advancement in engineering blasting.

Studying the dynamic response and failure mechanism of hazardous substances storage cabinet structures under internal combustible gas explosion loads can minimize the consequences of explosion accidents, reducing casualties and property losses, which holds significant engineering and social value. This study used methane mixed with air as the combustible gas in internal explosion tests conducted within a hazardous substances storage cabinet structure. Tests were performed under four gas cloud conditions: 1 m³, 8 m³, 27 m³ and 78 m³. Typical overpressure and displacement time-history curves from internal explosion were obtained, and the dynamic response was analyzed. The results show that the displacement response of the storage cabinet structure synchronized with the load response. As the overpressure load increased, the displacement of the storage cabinet wall increased accordingly, reaching their peak nearly simultaneously. The results of overpressure and structural response tests indicate that the peak value of the overpressure load measured in the test did not follow the expected trend, as the more extensive gas volume did not consistently result in higher peak overpressure values.

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 DBDP Hydropower Station, the largest hydropower station under construction in Pakistan, faces challenges related to blasting vibration affecting freshly poured concrete of the proposed intake tower of the diversion tunnel. Finite element calculation parameters were adjusted based on on-site blasting vibration monitoring data to address this issue. A numerical simulation method was utilized to analyze the blasting vibration response of the water intake tower under various blasting conditions and to identify factors influencing peak particle velocity (PPV). The study proposes measures to control blasting vibration. The results indicated that the maximum charge per delay, the delay time between blast holes, the advancing direction, and the detonation position significantly impact the intake tower's vibration. It is recommended that the maximum charge per delay and the delay time between blast holes be controlled to mitigate vibration on the fresh concrete. Additionally, adopting a backward blasting advancing direction and hole-bottom initiation is advisable.

To investigate the influence of different blast incision central angles and heights on a cooling tower's overall collapse effect, the structure's collapse process was simulated by ANSYS/LS-DYNA finite element software. The original model was modified to explore the effects of various blasting incision's central angles and heights. Five different blasting incision heights (14 m, 15 m, 16 m, 17 m, 18 m) and three blasting incision central angles (190°, 210°, 230°) were selected for orthogonal combination to analyze their impact on the collapse effect. The results indicate that the blasting incision's central angle significantly influences the distribution range of the collapse debris, while the blasting incision height plays a secondary role. The highest point of the pile is generally located along the collapse centerline and near the transverse fracture of the tower wall. The degree of fragmentation and location of fissures on the rear tower wall determine the height and location of the highest point of the debris pile. At a fixed blasting incision height, the vertical touchdown velocity of the structure decreases as the incision's central angle increases. Conversely, at a fixed incision central angle, the vertical touchdown velocity decreases and then increases with increasing incision height. The optimal demolition parameters for the cooling tower are a blasting incision angle of 210° and a blasting incision height of 17 m.

This study addresses the blasting demolition of an 18-story oval frame-core tube structure. Systematic analysis revealed that the structure's small height-width ratio and long span contribute to potential instability and collapse, with uneven stress distribution due to irregular shear wall placement within the core tube. To mitigate these challenges, delayed blasting and auxiliary weakening techniques were employed. The approach included pre-treatments such as splitting and cutting to transform the cylindrical structure into a wall-like form, reducing deviation during collapse. The building was divided into four blasting zones with increasing delay times, particularly extending the delay for the last two zones by 1 second to ensure sequential support point failure and prevent incomplete collapse. Additionally, the upper and lower double-incision folding blasting method was utilized to control vibration upon ground impact and enhance overall dissociation. The demolition process, lasting approximately 5 seconds, resulted in the building collapsing primarily along the designed direction with minimal backseat movement and evident structural failures. The sequential floor folding and concentrated pile blasting demonstrated effective demolition.

The impact of blasting vibration on surrounding buildings has been widely concerned. Based on the deep hole bench blasting project of Changtan Open-pit Coal Mine, the characteristics of the adjacent 11-story frame-shear structure office building are comprehensively analyzed. After several blasting vibration tests, the distribution characteristics of vibration velocity and main frequency in different directions were analyzed. The significance of elevation difference on vibration velocity in various directions was obtained through single-factor analysis. Finally, based on the dimensional analysis method, a vibration velocity prediction model under the influence of multiple factors was studied, proposed, and applied to the blasting safety charge design. The main conclusions are as follows: with the increase of floors, the primary vibration direction changes from horizontal radial (X) to horizontal tangential (Y), and finally to vertical (Z). In most working conditions, the PPV_x and PPV_y are not more than 0.17 cm/s and 0.213 cm/s, respectively, and the elevation has little influence. The PPV_z is concentrated in 0.05~0.41 cm/s, and the elevation amplification effect is significant in 7~11 layers. The maximum charge per delay, total charge amount, and horizontal distance are substantial for the three-axis PPV_s. The elevation difference is not significant for the PPV_x but significant for the PPV_y and PPV_z. The main vibration frequency is concentrated in 3~12 Hz, and some reach 16~30 Hz. Based on the vibration prediction model for the office building, combined with the blasting safety regulations and the blasting parameters under the most dangerous working conditions, the total charge of the bottom blasting should be within 10 267 kg, and the total charge of the deep hole bench blasting should be between 8268~8883 kg.

To systematically reveal the influence of laws of microwave radiation parameters (power, time) on the degradation of the mechanical properties of iron ore and the energy dissipation mechanism, and to improve the crushing efficiency of iron ore, this iron ore from Sishanling in Liaoning Province is the research object. By adopting a method combining microwave pretreatment, multi-scale mechanical tests, and microscopic tests, this thesis conducts static and dynamic impact tests as well as XRD tests on iron ore samples under different microwave actions. By analyzing the mechanical properties of iron ore subjected to various microwave treatments and utilizing the principles of energy conservation, this study elucidates the damage evolution characteristics and the laws governing energy evolution of iron ore under the coupled action of microwave and mechanical forces. The research results show that: (1) With an increase in microwave power and irradiation time, the sample mass decreases slightly, and the longitudinal wave velocity, uniaxial compressive strength, and elastic modulus exhibit a linear degradation trend. Microscopic tests have confirmed that the damage is caused by thermal stress cracking, rather than a change in composition. (2) The analysis of energy evolution indicates that microwave pretreatment diminishes the total input energy density of the sample, reduces the proportion of elastic energy, and elevates the proportion of dissipated energy. This phenomenon suggests a deterioration in the ore's storage capacity and a transition toward plastic yielding. (3) Dynamic impact tests show that an increase in microwave damage leads to a 45.58% increase in reflected energy, a 16.12% decrease in transmitted energy, and an increase in energy dissipation to 37.49%.

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.

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.