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.

This study focuses on the impact of charge structure on the distribution of blast pile morphology in a limestone mine. A combination of theoretical analysis, GDEM-BlockDyna numerical simulation, and on-site optimization tests were conducted to investigate the morphological distribution of step blasting and blast reactors. The change in blast pile morphology with different charge structures was analyzed. The results indicate that the looseness and throwing distance of the blast pile initially increase and then decrease with an increase in the upper charge proportion of the interval section. The height of the explosion pile generally decreases but shows an initial decrease followed by an increase when there is a large air interval proportion. Additionally, the slope angle of the blast pile increases with an increase in charge proportion in the upper section of the interval section but decreases when this proportion becomes too large. These findings demonstrate that explosive pile patterns vary according to charge structure. Furthermore, through numerical simulation methods, effective optimization can be achieved for charge structure, leading to improved on-site explosion patterns and economic benefits for mining operations.

This study aims to investigate the stability evolution of the safety roof pillar during the transition from open-pit to underground mining in Longshou mine under the influence of blasting vibration. A numerical calculation model was established based on the current mining area conditions. The most critical position of the safety roof pillar was determined through calculations, and a two-dimensional numerical model for this position was developed using top-level mining as an example. By calculating blasting parameters and equivalent elastic boundaries, we obtained the peak blasting load transmitted from cutting holes, auxiliary holes, and peripheral holes to the excavation surface. Subsequently, numerical calculations were conducted to assess the stability of the safety roof pillar after applying an equivalent blasting load to the excavation face. The results indicate that each delayed blast caused displacement and vibration velocity peaks, with maximum displacement observed at monitoring points inside the safety roof pillar closest to the blast site. Vibration velocity spreads spherically around the blasting operation position into surrounding rock mass. Based on criteria related to blasting vibration velocity and rock damage assessment, it can be concluded that overall there is no or only slight damage present in the safety roof pillar. Additionally, analysis reveals that maximum principal stress remains lower than tensile strength of rock mass without any significant formation of a tensile fracture plastic zone on the safety roof pillar. In general, the designed thickness of the safety roof pillar meets requirements for open-pit to underground mining. However, due to actual geological complexities beyond what is captured by the numerical model, it is essential to continuously observe and monitor changes in the safety roof pillar to ensure its stability during ongoing mining operations.

In response to the poor excavation effect of traditional blasting in complex lithology tunnels, a method called advanced cutting control blasting is proposed based on the research of traditional smooth blasting and pre-splitting blasting. This method involves conducting the blasting around weak surrounding rock areas after tunnel contouring hole blasting. A quasi-three-dimensional model was established, and numerical simulations were conducted using the fluid-structure interaction (ALE) algorithm and ANSYS/LS-DYNA finite element analysis software to compare the advanced cutting control blasting method with traditional pre-splitting and smooth blasting methods. The results show that compared to smooth blasting and pre-splitting, advanced cutting control blasting reduced the depth of damage around the tunnel contour by 6.85% and 10.08%, respectively. Based on simulation results, field blast test plans were designed, and comparative tests between smooth surface blasting and advanced cutting control blasting methods were carried out. The blast results demonstrated that after adopting the advanced cutting control method, the tunnel contour had good shaping effects without block falling or collapse in weak surrounding rock areas, while over-excavation was effectively controlled. Three-dimensional cross-sectional scanning data and statistical results of post-blast sections indicated that compared to well-performing smooth surface blasting, maximum over-excavation decreased by 35.98%, average over-excavation decreased by 25.60%, concrete consumption decreased by 26.3%, and flatness standard deviation increased by 24.29%. This method has been verified through field practice as it reduces over-excavation while mitigating blast damage in complex lithology areas, thereby improving tunnel retaining rock flatness.

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.

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 non-pillar sublevel caving method is extensively employed in underground metal deposits due to its advantages of high mining efficiency, simple structure, and enhanced safety. In order to address the issues associated with the laborious design process and insufficiently intuitive simulation effect of medium-length hole blasting using traditional pillarless sublevel caving methods, this study conducted a simulation and application research on the medium deep hole blasting process based on the Aegis blasting design and analysis software. Firstly, this paper introduces the module composition and functions of the software while summarizing the simulation analysis process. Secondly, two key technologies were investigated: utilizing model boundaries to confine the blasting space and employing staggered states of blasting energy to verify borehole network parameters. Finally, numerical simulations were performed on medium-length hole blasting in a specific underground mine with non-pillar sublevel caving method using this software. The research findings suggest that the explosion energy in a single row of blast holes is concentrated and fills the entire explosion chamber. The design of continuously coupled charging structure and a powder factor of 0.3 kg/t is deemed reasonable in this context. It appears that there exists a tangential state for the blasting cavity walls between adjacent blast holes, indicating that the energy between rows may not be sufficient to completely break the rock mass. The distance between blast holes, which is approximately 2.2 m, seems slightly larger. Multiple routes were analyzed to predict the distribution of blasting fragmentation masses, all showing a high proportion of large blocks, consistent with field engineering practice results. For instance, based on photos taken after one blasting event, it was observed that large blocks accounted for 18.03% of the total pile volume. Simulation results from Aegis software analysis indicate that the large spacing between blast holes may be a primary factor contributing to this high block rate. Furthermore, through conducting 12 blasting tests on six mining routes within an experimental section and verifying these results through simulation analysis, consistent outcomes regarding proportions of block size and mass were obtained. This effectively supports the practical application efficiency of the software on-site. Overall, these findings contribute valuable insights into optimizing blasting techniques in rock excavation projects by considering factors such as explosion energy concentration and hole spacing to achieve desired fragmentation outcomes while minimizing undesirable block formation.

Feed and its additive dusts have a high combustion heat, which poses significant risks of dust explosions during production, thereby threatening life and property safety. Currently, premix inhibitors are widely used as explosion suppression measures. However, traditional inhibitors are inedible and cannot be added to feed dust to achieve explosion suppression. Therefore, this study focuses on the dust of DL-methionine (DLM), a primary additive in feed, and investigates the effect of self-synthesized phytic acid-cytosine (PA-CY), an edible biomass-based compound with nutritional value and environmental friendliness, on the flame propagation characteristics of DLM dust explosions. The flame propagation process was recorded through high-speed photography and visualized in a vertical pipe while calculating the flame velocity. Additionally, thermocouples were used to monitor changes in flame temperature. The results indicate that as the mass fraction of PA-CY increases, the luminosity of DLM dust explosion flames consistently decreases, severely disrupting the flame structure. After adding 20% PA-CY, there is a reduction of 50.0%, 52.2%, and 46.7% in peak velocity (from 27.66 m/s to 13.83 m/s), average velocity (from 14.39 m/s to 6.88 m/s), and peak temperature (from 1014℃ to 540℃) respectively. Moreover, when the mass fraction of PA-CY reaches 30%, ignition of the dust cannot occur indicating significant inhibitory effects provided by PA-CY.

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 blasting construction of water conservancy projects is characterized by its long duration and large scale. However, traditional methods for blasting design and construction control are inadequate to meet the requirements of current water conservancy project development. Therefore, it is crucial to study and establish a platform-based, networked, and intelligent blasting design and control system with significant engineering significance. To achieve this goal, this research adopts a front-end and back-end separation method using the Angular framework and SpringBoot framework based on BIM (Building Information Modeling), WebGIS (Geographic Information System), and developed blasting design software. The system comprises an intelligent blasting design module, three-dimensional visualization module, digital blasting control module, as well as an intelligent safety evaluation and prediction/warning module. This integration enables intelligent blasting design along with comprehensive auditing functions throughout the entire process. Importantly, the system can select control points on the excavation contour line for intelligent blasting design based on actual site conditions. It generates blast design schemes that undergo review using a model parameterized dynamic joint cropping method before being uploaded. This approach promotes standardization, informatization, and digital management of the entire blasting process while enhancing real-time interactive collaboration among various units involved in designing, constructing, supervising hydropower stations. The application of this system in slope blasting and excavation projects at Yebatan Hydropower Station demonstrates its effectiveness in carrying out blast designs while improving control efficiency. Consequently, it provides valuable technical support for slope blasting designs during hydropower station excavations.