Ore crushing is a crucial phase in hard rock mining and mineral resource recovery, significantly focusing on optimizing the energy consumption balance between blasting and mechanical crushing. This study analyzed industrial test data from an iron mine to explore the relationship between parent rock size distribution characteristics and mechanical crushing energy sensitivity, providing a theoretical foundation for process optimization and energy efficiency improvement. Initially, the connection between the key parameters of the parent rock size distribution curve and crushing power consumption was investigated. Subsequently, the maximum block size under the screen (D75) was identified as a sensitive indicator for crushing power consumption through correlation analysis. Finally, a theoretical model based on shared blasting control was developed, utilizing an optimal parent rock size distribution curve, R=1-\exp \left[-{\left(\frac{X}{282.1}\right)}^{1.69}\right] to control the block size. Field application of this model demonstrates a cost reduction of 17.63%, affirming its potential for enhancing energy management and cost efficiency in mining operations.

During drilling and blasting of open-pit mining in high and cold regions, water inrush or freezing often occurs on the borehole inside. This phenomenon creates a decoupled charge structure with water and ice, affecting the blasting effect and the rock-breaking mechanism under decoupled conditions. To determine the geometric parameters of the blasting crater and analyze the blasting effect under three types of decoupling medium in the high-cold area, a series of tests were conducted on the blasting effects of different decoupling charges in the Karma open-pit mining in Tibet. Based on the Livingston curve fitting results, the blasting parameters were optimized and applied to on-site engineering blasting. The results indicated significant differences between the visible volumes of the blasting crater and the crushed funnel at burial depths of 1.09~1.49 m. However, these volumes resembled burial depths of 1.49~1.69 m. Compared to the air-deck decoupling, the peak particle velocities under water and ice decoupling were reduced by 25.33% and 11.24%, respectively. The critical charge depths varied among the three decoupling materials, with water decoupling having the most significant critical depth, ice decoupling charge, and air-deck decoupling having the shallowest. The charge weights required for water and ice decoupling and ice decoupling were 18.9% less than those for air-deck decoupling. In multi-hole bench blasting, the explosive factor for water and ice decoupling was reduced by 18.2% compared to air-deck decoupling, and the rate of large fragments decreased from 8.9% to 4.3%. This indicated that water and ice decoupling charges made the energy distribution of explosives more uniform.

With the rapid advancement of modern industry, the demand for high-performance materials has grown significantly. Titanium/duplex stainless steel composite plates, known for their exceptional corrosion resistance, demonstrate vast potential for diverse applications. In this study, a bimetallic composite plate comprising TP270C titanium alloy and SUS821L1 high-strength duplex stainless steel was fabricated using explosive welding. The microstructural characteristics of the composite plate interface were thoroughly investigated through metallographic microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and electron backscatter diffraction (EBSD). Additionally, the welding quality was systematically evaluated. The results showed that the welded interface exhibited an intermediate structure between flat and wavy when the interface deposition energy was low. In contrast, the welded interface displayed a wavy structure at higher interface deposition energy. Element diffusion and grain refinement were observed in the regions adjacent to both interfaces. Complete recrystallization predominated in the welded interface, molten zone, and adiabatic shear band. Near the welded interface, titanium underwent partial recrystallization, while duplex stainless steel exhibited a combination of partial recrystallization and deformed grains. Localized thermal accumulation facilitated grain growth in the molten layer, whereas titanium particles encapsulated within the molten layer exhibited refined grain structures. Mechanical performance tests indicated that the sample with higher interface deposition energy achieved a 40.33% increase in shear strength and a 4.52% improvement in bending strength compared to the sample with lower interface deposition energy.

To investigate the rock mass crack propagation pattern in deep-buried tunnels during drilling and blasting excavation, two combined model tests (labeled as Model 1 and Model 2) consisting of multiple cement mortar blocks were carried out. The dimensions of the models were both 180 cm×80 cm×25 cm (length width height). Among them, the matrix size was 60 cm×80 cm×25 cm, and two sides had single and multiple joints. Furthermore, a thorough analysis was conducted to determine the influence of dynamic loads stemming from nine cumulative explosions on the crack propagation in a matrix by applying various static stresses, particularly on the direction of the applied static loading. The experimental results reveal that cracks emerge on both Model 1 and Model 2 surfaces along the direction of static stress loading when the static stress increases from 0.5 MPa to 5 MPa. The crack propagation direction forms an angle on the loading direction, and the main crack is longer than 60 cm. A blasting funnel contour with about 30 cm diameter is formed on the bottom of Model 1, which does not fall off. In comparison, a funnel with about 52 cm diameter and a 10 cm depth is formed on the bottom of Model 2, which has fallen off. Numerical analysis verified that the static stress has a guiding effect on the propagation direction of blasting cracks, which is consistent with the model test results. The difference was that the length of the main crack calculated by numerical calculation was smaller than that of the model test. Finally, the reason for this deviation was analyzed.

Numerical simulation is a vital tool for studying the dynamic characteristics of rock, with the accurate determination of models and parameters being the key to ensuring the reliability of simulation results. Among the 34 parameters of the RHT model, 19 parameters can be obtained through experimental and theoretical calculations, but the remaining 15 are challenging to determine. Nineteen basic parameters of anhydrite were obtained through experimental analysis and theoretical calculation to identify the model parameters suitable for anhydrite. Furthermore, the LS-DYNA performed SHPB simulation tests on the 15 challenging parameters. The sensitivity of stress-strain curves to these parameters was compared, and the values were optimized. Parameters with high sensitivity were identified through orthogonal testing. Finally, simulation results were compared with laboratory test results. The findings indicate that RHT parameters B, , n, D₁, n_f, P_comp and N have minimal impact on the stress strain curve, while parameters A, , , Q₀, , ξ, and A_f significantly influence the curve. Furthermore, the parameters with a significant impact on the stress-strain curve were determined by orthogonal tests, and the RHT model parameters fitting the SHPB impact test curve were obtained. Under varying loading strain rates, the dynamic stress-strain curves and failure patterns of anhydrite simulation tests were consistent with laboratory tests, verifying the suitability of the model parameters for anhydrite.

Since uneven stress on the cutter head can easily lead to surface collapse accidents when a shield machine passes through the silt-rock strata, the rock stratum can be blasted and broken by drilling blast holes on the ground surface before the shield machine arrives. However, the seismic waves generated by the blasting would threaten the safe operation of adjacent gas pipelines. In order to study the vibration characteristic of adjacent gas pipelines during blasting in silt-rock strata, the rock breaking project of silt-rock strata in the shield section of Hengqin Station and Hengqin North Station of Zhuhai Metro was selected as the research background. Firstly, the on-site blasting vibration was tested. Then, the ANSYS/LS-DYNA software was used to simulate the blasting process and invert the physical and mechanical parameters of the materials at the blasting site. Finally, the vibration characteristic of the gas pipeline was analyzed. The research results show that the PPV (peak particle velocity) on the pipeline decreases with the increase of the horizontal distance from the explosion source in the axial direction of the gas pipeline. Meanwhile, the maximum PPV position is perpendicular to the center line of the blast holes. Furthermore, the surface PPV above the gas pipeline decreases along the pipeline axis as the horizontal distance from the explosion source increases, and the maximum PPV position is also perpendicular to the center line of the blast holes. Besides, there is a functional relationship between the surface soil PPV₂ along the axial direction of the gas pipeline and the PPV₁on the outer wall of the gas pipeline, which is V₂=0.60V₁+1.29. More importantly, the PPV of the gas pipeline's inner and outer of the gas pipeline are basically the same.

With the continuous development of blasting equipment, the popularization of high-precision detonator detonators and electronic detonators have been widely used in open-pit bench blasting. However, the definition is vague in the selection of the maximum amount of initiating charge and the distance from the detonation source to the vibration measurement point for the linear regression analysis of the Sadovsky formula when the vibration measurement point is close to the blasting area, and the dispersion position of the blast hole cannot be ignored. A proportional distance was used to measure close-range blasting vibrations by hole blasting. The total charge with a delay interval smaller than 8 ms or the charge quantity nearest to the vibration measurement point was selected as the maximum blasting charge in a section. The distance between the detonation source and the vibration measurement point was selected as the three-dimensional distance between the center of the hole range of the maximum blasting charge and the vibration measurement point or the three-dimensional distance between the hole and the nearest vibration measurement point. The one with a smaller proportional distance was selected for linear regression by comparing the group proportional and single proportional distances. The results show that it has relatively accurate linear regression using this method for the same direction or near the direction of the vibration point value after the noise reduction process.

On-site double-hole slitting blasting experiments were conducted to study the effect of controlling fracture damage by double-hole slitting blasting. A test double hole slitting blasting model was constructed using ANSYS/LS-DYNA software, and its crack propagation and changes in gas unit pressure on the hole wall were compared and analyzed. The on-site results indicate that an intersecting fracture surface is formed between the two blast holes in the direction of the cutting seam after the explosion, and the half-hole residue is more obvious. Besides, the cracks will still develop towards the cutting direction by changing the cutting angle to 157°, and the guiding effect of the cutting seam is not affected by the change in angle. Meanwhile, the fracturing effect of adding empty holes between blast holes is better than that of non-empty hole slot blasting, which indicates that the existence of empty holes can effectively improve the directional fracture effect of slot blasting. The model results of the crack propagation and damage are consistent with the on-site results. By comparing and analyzing the double hole slit blasting and ordinary smooth blasting models, the superposition effect of stress waves causes the development of cracks between the holes to deflect, which forms a crack void between the two holes. Though analyzing the peak pressure of gas units around the hole wall at 0°~90°, it is found that the time when the pressure peak reaches the slit direction is earlier than that in the non-slit direction. More importantly, the pressure peak decreased significantly, and then the curve gradually tended to flatten during the slit blasting range of 0°~15°. The larger the angle, the smaller the peak change. The slit tube effectively controls the distribution of explosion energy during the explosion process, which forms stress concentration at the slit, with the maximum stress peak being about four times higher than that in the vertical direction.

Researching controlled blasting technology for hazardous rock bodies in complex environments holds significant theoretical importance and provides valuable reference points for enhancing highway construction efficiency and mitigating potential risks. This study focuses on the Gulin-Jinsha highway construction project, aiming to eliminate the dangers posed by hazardous rock bodies during construction. Six scanning stations were established using 3D laser scanning technology to create a high-precision 3D Digital Terrain Model (DTM) of the hazardous rock bodies. Additionally, four object detection lines were deployed using a high-density electrical method to achieve 3D visualization of the geological features in the hazardous rock area. A fracturing test was conducted based on the high-precision 3D model. The designed depth of the shell hole was 70% of the height of the hazardous rock body, with fracturing pipes connected in series and each pipe carrying a total charge of 720 g. The results demonstrated that the constructed high-precision 3D model accurately reflects the morphological characteristics of the hazardous rock body, providing reliable information for the blasting design. The fracturing pipes showed effective fracturing performance, facilitating the removal of the hazardous rock body during subsequent stages. This method offers a viable reference for similar projects, showcasing the potential for efficient and safe removal of hazardous rock bodies in complex environments.

Abstract: Vibration is a primary detrimental effect generated by blasting operations, and accurately evaluating its impact remains crucial and challenging. Based on the blasting excavation of a tunnel under the Central Yunnan Water Diversion Project, this study combines numerical simulation and field investigation to assess the damage characteristics of buildings affected by various factors. The results show that blasting vibration causes “X-shaped” cracks at the four corners of windows and doorways, while uneven settlement leads to 45° diagonal cracks. Subsequently, time-frequency analysis was performed on vibration data from buildings at varying distances from the blast source. The findings indicate that forced vibration predominates in building foundations, with minimal free vibration and quickly attenuating after the blasting load ends. As horizontal distance increases, the main frequency and blasting vibration energy exhibit a downward trend based on Fast Fourier Transform (FFT) analysis. However, the main frequency is less sensitive to distance changes than energy. Additionally, the sensitivity of energy to distance varies across different frequency bands. Generally, energy in each frequency band rapidly attenuates close to the blast source, with slower attenuation as distance increases. Furthermore, as the distance from the last source increases, there is a shift in energy from higher to lower frequency bands towards lower frequency bands, and the effect of low-pass and high-filter results in distinct variations in energy attenuation within different frequency bands. Finally, the study highlights a significant disparity between human perception of blasting vibrations and building safety standards. Based on this observation, a comprehensive evaluation method is proposed to combine structural damage assessment with considerations of the human settlement environment.