Due to the complex terrain and geological conditions in the blasting area, as well as errors in monitoring instruments, reflections of vibration propagation medium, and interference from magnetic fields, a significant amount of noise is often present in the original blasting vibration signals collected. To address this issue, a signal noise reduction smooth model based on complementary ensemble empirical mode decomposition (CEEMD) is proposed. Firstly, the measured blasting vibration signal is decomposed using CEEMD and an algorithm for low-pass filtering is established based on the obtained intrinsic mode function (IMF) component from the decomposition. Additionally, an objective function is constructed to calculate the optimal solution according to similarity and smoothness criteria for filtering algorithms. The resulting filtering algorithm model represents an optimal denoising smooth model for blasting vibration signals. To verify our noise reduction smooth model, a simulation signal is constructed and applied to actual open-pit deep-hole blasting vibration signal research. Finally, the noise reduction effects of empirical mode decomposition (EMD) method, wavelet threshold method, CEEMD-wavelet threshold method, and filter algorithm model BP3 are quantified and compared using two indexes: signal-to-noise ratio and root-mean-square error. It has been confirmed that the proposed noise reduction smooth model effectively reduces noise in open-pit blasting vibration signals. The findings demonstrate that our CEEMD-based noise reduction smooth model for open-pit deep-hole blasting vibrations possesses excellent denoising capabilities while preserving essential characteristic information from the original signals. Furthermore, the denoising effect of the proposed model surpasses that of EMD method, wavelet threshold method, and CEEMD-wavelet threshold method.

In order to demolish a 57 m high double-cylinder ammonium nitrate granulation tower in a complex environment, this study analyzes the structural characteristics of the tower, including its large potential energy and uneven mass distribution. A blasting method was designed with intermediate initiation and sequential detonation towards both sides to achieve a controlled collapse effect through “directional blasting + internal convergence”. The blasting design includes trapezoidal cut notches with strictly controlled perimeter and height. The bottom supporting walls are partially retained, and highly symmetric directional windows were created at specific heights. The demolition was carried out using high-precision nonel detonators combined with delayed initiation inside the holes and external relays outside the holes. Through theoretical analysis and calculations, the final blast notch length was determined as 13.5 m with a height of 3.5 m. To validate the design scheme, LS-DYNA simulation software was used to establish a three-dimensional finite element model of the granulation tower for pre-collapse analysis. Simulation results show that the collapse process takes approximately 8.8 seconds without any significant forward movement or toppling during collapse, indicating that the overall blasting parameters selected in this scheme are reasonable and can achieve the desired demolition effect.

Gaseous detonation synthesis is a novel approach for the production of carbon nanomaterials. This method offers several advantages over other techniques, including rapid reaction kinetics, diverse product types, high yield, exceptional purity, straightforward operation, and cost-effectiveness. These benefits make it highly suitable for promoting the industrial-scale manufacturing of carbon nanomaterials. To elucidate the current research and development status of gaseous detonation-synthesized carbon nanomaterials, this paper provides an overview of the necessary instruments and equipment, experimental procedures, theoretical calculations, and product characterization methods employed in this synthesis technique. Additionally, it summarizes the technologies and methodologies used to synthesize various carbon-based materials such as carbon-coated nanometallic particles, carbon nanospheres, carbon nanotubes (CNTs), carbon dots (CDs), and carbon nanocapsules via gaseous detonation synthesis. The morphology of these synthesized products is analyzed along with their structural features and performance characteristics. Furthermore, this study explores the potential applications and technological advancements associated with these newly developed gaseous detonation-synthesized carbon nanomaterials to lay a solid theoretical foundation for rational design optimization and large-scale production of nanostructured materials in line with industry standards in explosive engineering. Current research indicates that the synthesis of detonation should be integrated with both macroscopic detonation theory and microscopic particle growth. The investigation of detonation wave engine and the analysis of detonation cell structure have become prominent areas of study, particularly in understanding the relationship between macroscopic detonation cells and the microscopic synthesis process of nanomaterials. However, a significant challenge remains in comprehending the growth mechanism of particles synthesized through detonation on a micro-scale, necessitating the utilization of molecular dynamics and lattice Boltzmann calculation methods for resolution.

The simulation test of blade loss in an aero engine plays a crucial role in casing containment design. The main challenge lies in controlling the breaking of rotor blades when they reach their maximum allowable speed. To investigate the optimal separation structure for rotor blades with artificial separation, two types of TC4 titanium alloy plates with Ⅴ-shaped grooves, one with a single hole and another with double holes at the center, were designed using explosive separation method. The selected size for the TC4 titanium alloy plate was 100 mm×80 mm×23 mm. The AUTODYN numerical simulation software's Smoothed Particle Hydrodynamics (SPH) algorithm was employed to conduct simulation calculations. Experimental comparisons were made on the damage and additional kinetic energy caused by five different schemes involving these two structures. Results indicated that scheme Ⅱ and Ⅴ failed to break off successfully, while scheme Ⅲ resulted in significant damage to the template. On the other hand, schemes Ⅰ and Ⅳ demonstrated better ability to separate the template. Under identical charge conditions, it was observed that the displacement of double-hole structured plates after fracture was significantly greater than that of single-hole structured plates with Ⅴ-grooves on both sides. Further analysis revealed that the Ⅴ-shaped slotted structure could reduce plate damage, enhance explosive energy efficiency, and minimize additional kinetic energy exerted on the plate. Moreover, compared to double-hole structures, this slotted structure also reduced peak speed by 20% and escape speed by 40%.

Air overpressure generated from the blasting excavation may affect the safety of surrounding structures. The blasting operation area of the horizontal tunnel of the second phase of Meizhou Pumped storage power station is only 81 m away from the steel accident gate of the upper drainage tunnel of the second phase project, which has been built and put into the operation in the first phase. However, the blasting may affect the operation stable of the accident gate. Therefore, taking the blasting excavation of the horizontal hole above the water diversion of the second phase of Meizhou pumped storage power station as the object, the field monitoring of blasting air overpressure was carried out. The distribution rule of blasting air overpressure and its influence on the safety of the emergency gate in the upper reservoir of Meizhou pumped storage power station were analyzed, which provided support for analyzing the influence of blasting air overpressure on the safety of the emergency gate in the upper reservoir. The blasting air overpressure monitoring data show that the air overpressure level in front of the accident gate about 80 m away from the blasting master surface is distributed at 0.63~3.46 kPa, which is much smaller than the suggested corresponding blasting safety control standard of 100 kPa. The protective facilities before the gate can effectively reduce the air overpressure at the gate position, and the measured air overpressure in the fourth and fifth blasting is reduced by more than 55%. When the single and total charge volume are effectively controlled, the measured air overpressure value is much smaller than the suggested control standard value. Besides, there is no abnormality in the field macro investigation and other detection data, the blasting construction does not affect the safe operation of the accident gate on the reservoir.

In urban centers, there are numerous old masonry buildings that possess poor seismic performance and may suffer damage under the effects of blasting. To investigate the dynamic characteristics of these structures when subjected to blasting, a strong motion instrument was installed near a blasting site on an old masonry building. This allowed for observation of both instantaneous and cumulative damage effects on the structure. By analyzing records of blasting acceleration and velocity in both time and frequency domains, it is concluded that the dynamic characteristics of the masonry structure can be better identified using blasting velocity rather than acceleration. Additionally, it is found that the transverse resonance of the masonry structure is most influenced by the blasting seismic velocity. Furthermore, both blasting seismic velocity and acceleration can approximately identify low order translational and torsional frequencies of the masonry structure. However, when calculating natural vibration frequency, it is observed that using blasting velocity yields a lower value (1.8%~3.4% lower) compared to calculations based on ground pulsation methods. This discrepancy arises because blast vibrations provide a more accurate reflection of structural response under larger vibrations. Moreover, frequent blasts may induce nonlinear responses in old masonry structures. By monitoring changes in natural vibration frequency over time due to long-term exposure to blasts, it is determined that with increasing blast frequency, first-order torsional frequency decreases by 4%, second-order transverse frequency decreases by 3.6%, and second-order longitudinal frequency decreases by 5.2%. These reductions occur even though individual blasts meet safety regulations, thus highlighting the importance of considering cumulative damage effects from long-term exposure to blasts for old masonry structures with poor seismic capacity during safety monitoring.

In order to study the vibration response of the interlaid rock in the small clear distance tunnel under the blasting load, a field blasting vibration test was carried out based on the blasting project of the Xiaolongmen tunnel. The improved variational mode decomposition (VMD) and multi-scale permutation entropy (MPE) algorithm were employed to denoise the blasting vibration signal. Subsequently, the differences in vibration characteristics between the left arch waist (non-interlaid rock area) and right arch waist (interlaid rock area) of the tunnel were analyzed, along with a comparison and analysis of seismic wave attenuation characteristics generated by cut hole blasting and surrounding hole blasting. The results demonstrate that the improved adaptive VMD-MPE algorithm enables automatic determination of modal number K and penalty factor α while effectively eliminating noise from the vibration signal, reducing subjective decision-making influence. During posterior excavation tunnel face blasting, interlaid rock exhibits significant amplification effects on blast vibrations. Peak particle velocity (PPV) values are higher in interlaid rock compared to non-interlaid areas. However, vibrations attenuate faster within interlaid rock regions. Additionally, analysis reveals that low-frequency vibrations below 40 Hz account for a substantial proportion of energy within interlaid rock areas when comparing frequency characteristics at measuring points between non-interlaid and interlaid regions. Attention should be given to these low-frequency vibrations as they are more likely to induce resonance in supporting structures, posing higher risks of damage or destruction within interlaid rock zones. By analyzing the blasting vibration characteristics of the cut hole and the surrounding hole, it can be found that the vibration velocity generated by the surrounding hole blasting in the surrounding rock behind the tunnel face is greater than that of the cut hole blasting within the range of the scale distance (SD) which is less than or equal to 11.57 m kg^1/3 due to the effect of 'corner weakening' and the influence of the seismic wave propagation path. After exceeding the critical value of SD, the vibration velocity generated by the cut hole blasting is greater.

In order to address the problem of predicting blasting vibration in complex geological conditions at open-pit mines, an improved BP neural network prediction model based on Mahalanobis distance discrimination (MD) and principal component analysis (PCA), namely MD-PCA-BP model, is proposed. By combining the monitoring data of blasting vibration at Changtan open-pit mine in Inner Mongolia, outliers in the monitoring data are eliminated using the Mahalanobis distance discrimination method. Then, the principal component analysis method is employed to reduce the dimensionality of factors affecting blasting vibration and obtain three principal component factors. The scores of each principal component factor are calculated, and finally a nonlinear relationship between blasting vibration and principal component scores is constructed through BP neural network to establish the prediction model based on MD-PCA-BP. The results show that the fitting degree between predicted values and measured values of blasting vibration velocity prediction model established based on MD-PCA-BP reaches 0.94, indicating high prediction accuracy of this model. When compared with Sadovsky empirical formula, two improved elevation empirical formulas, MD-BP model, PCA-BP model, and BP model, most of the prediction errors of MD-PCA-BP model are within 10%, demonstrating higher reliability and accuracy compared to empirical formulas and unimproved BP prediction models. The blast vibration prediction model based on MD-PCA-BP exhibits good predictive performance for blast vibration velocity in complex terrains.

The shock wave generated by underwater explosions has a significant destructive impact on the surrounding environment. Therefore, it is crucial to implement bubble curtain protection for blast area safety. This study aims to investigate the influence of the number of bubble curtain layers on attenuating underwater explosion shock waves. An underwater explosion model with free water and varying numbers of bubble curtain layers was established using AUTODYN finite element software. Through experimental validation of the numerical model, a formula for calculating peak overpressure of the shock wave was derived, and the impact of different numbers of bubble curtain layers on shock wave attenuation in water was compared. The results demonstrate that employing a bubble curtain can effectively reduce peak overpressure from an underwater blast shock wave, achieving an attenuation ratio as high as 83%. Furthermore, increasing the number of bubble curtain layers can further enhance this attenuation effect, reaching more than 94% reduction in peak overpressure. Specifically, when comparing two-layered and one-layered bubble curtains at a distance of 12 m from the detonation center behind the bubble curtain, there is a reduction in peak overpressure by 61.94%. Similarly, using a three-layered bubble curtain leads to an additional decrease in peak overpressure at this distance by 11.38% compared to using a two-layered one. However, when utilizing four-layered curtains instead of three-layers ones, there is only a marginal decrease in peak overpressure (6.42%) at this same distance. In conclusion, implementing a bubble curtain significantly weakens shock waves within water bodies during explosive events. Moreover, fewer layers within the bubble curtain result in greater attenuation effects. However, diminishing returns are observed with each subsequent increase in layer count.

In order to analyze the attenuation effect of multi-layer bubble film on underwater explosive shock wave, an underwater explosion test was conducted to obtain shock wave parameters with a No. 8 industrial electric detonator as the explosion source. The bubble film was designed with different specifications and different layers of air insulation structure. Furthermore, the shock wave overpressure peak value and specific shock wave energy were compared based on the shock wave parameters. The results show that the attenuation rate of shock wave overpressure peak increases with the increase of bubble film number, with the attenuation rates of 1#, 2#, 3#and 4#bubble film increasing from 48.32%, 86.08%, 87.87% and 90.34% to 89.10%, 91.33%, 91.45% and 92.37%, respectively, which implies that the normal film has less influence on the attenuation of underwater shock wave without air interlayers. Specifically, a larger bubble diameter can reach a better attenuation effect with the same number of layers, which indicates that the bubble plays an important role in attenuating shock waves. In addition, the specific shock wave energy consumption of the bubble film is more than 98.50%. In practical applications, bubble film can be used as a protective material, which can effectively reduce the harmful effects caused by shock waves on the protected objects.