The geological structure of the Ying Liang-bao hydroelectric underground power-house is complex due to the development of surrounding rock fissures, messy lithology, and a rock body with "hard, broken, miscellaneous" characteristics. Excavation and molding pose difficulties while pre-splitting blasting has poor effects. To address this issue, we conducted a systematic blasting test combined with pre-splitting for central groove construction on layer III of the power-house. In initial tests, both sides of the wall exhibited significant breakage after blasting and traces of presplitting holes were not clearly visible when linear charge density was nearly 100 g/m lower than standardized calculation values. Acoustic testing data revealed that average longitudinal wave velocity in the rock mass body was 4.03 km/s indicating overall poor integrity. Additionally, segmental wave velocities along axial depths from 0~1.5 m, 1.5~3.9 m and 3.9~7.4 m were found to be 2.59 km/s, 3.58 km/s and 4.70 km/s respectively suggesting segmented integrity differences in depth direction. Based on these findings an average single-hole linear charge density for pre-splitting blasts during excavation was determined to be between 0.123~0.284 kg/m with different densities selected according to varying depths while small charge rolls were evenly spaced for each section. The results obtained through testing and application have been positive ensuring basic formation of wall surfaces while significantly increasing half-porosity levels.

The impact of fragmentation size and gradation on the stability and permeability of rockfill in hydraulic engineering is of great significance. Accurate prediction of fragmentation size has become a key focus in rock blasting research. In this study, a PSO-BPNN model is developed based on the Backpropagation Neural Networks (BPNN) with optimized network weights and biases using the Particle Swarm Optimization (PSO) algorithm. The model is trained and tested using representative blasting data, and its reliability and applicability are validated through its application in the Hunyuan Pumped Storage Power Station project in Shanxi. Results demonstrate that the PSO-BPNN model exhibits short computation time and high reliability for predicting fragmentation size, with a maximum relative error between the model output and actual average fragmentation size of 6.56%. Therefore, this model demonstrates high predictive accuracy and applicability, providing precise guidance for construction of rock-fill dams at the Hunyuan Pumped Storage Power Station in Shanxi province.

The distribution of blasting fragmentation in open pit mines has a direct impact on subsequent excavation, transportation, and crushing operations. To effectively control the fragmentation distribution of blasted rocks in different regions of graphite mines, a new model for evaluating rock blastability was developed using the K-means unsupervised cluster learning method and entropy weight TOPSIS evaluation method. Evaluation indexes including rock density, dynamic energy dissipation rate, dynamic compressive strength, average strain rate, and brittleness index were selected. Through entropy weight calculation, it was determined that the degree of rock breakage is most influenced by the brittleness index and least influenced by the average strain rate. The model was then applied to an actual graphite mine to assess its effectiveness. The rock blastability was divided into 10 grades based on this evaluation model. The average particle size of rocks under different grades was calculated and it was observed that as blastability grade increased, so did the average particle size. This finding demonstrates clear classification characteristics and validates the efficacy of our model. From the perspective of rock mass type of graphite ore, the rock explosibility is ranked from easy to difficult: schist, gneiss, granodiorite, mixed rock. Combined with the analysis of microscopic observation results of graphite ore, it can be seen that the lithology changes from schist to mixed rock, and the graphite crystalline content in the rock decreases, and the graphite ore explosibility grade is also higher and higher. Additionally, there exists a linear positive relationship between density/energy dissipation rate/dynamic compressive strength with rock blastability while negative correlation is observed with respect to average strain rate/brittleness index.

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.

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 deep hole bench blasting in open-pit mines, several issues arise including high consumption of explosives per blast, large bulk and foundation ratio, increased overall cost, inadequate loose blasting pile for shovel loading, and excessive blasting vibrations that affect slope stability. This study focuses on the controlled blasting project of deep-hole benches in Duobaoshan open-pit mine. Theoretical analysis was conducted to establish an analytical formula for the stress field caused by hole-by-hole blasting. The parameters such as hole and row spacings, minimum bottom resistance line, and delay time between holes were determined based on this formula. The LS-DYNA software was utilized to analyze the blasting stress and crushing range under these parameters. Furthermore, six groups of industrial field tests were carried out at Duobaoshan open pit mine using different blasting parameters. These tests aimed to determine the variation patterns of powder factor, fragmentation size, and looseness characteristics among different explosives. The optimized parameters for controlled deep hole bench blasting in Duobaoshan open-pit mine were verified and determined through these experiments. The main research findings are as follows: (1) Under the coupling charge condition of Duobaoshan open-pit blasts and utilizing theoretical derivation and analysis of stress fields from hole-by-hole initiation method, it was found that the influence of stress field distribution is limited to front and rear holes with a delay time between holes set at 17 ms. (2) UAV tilt photography technology along with mobile phone photography can be employed to collect data on detonation piles' characteristics and lumpiness size at blast sites. Analysis based on collected data provides effective insights into looseness levels. (3) For the 178 mm of the hole diameter and 17 ms of the holes' delay time of the deep hole bench blasting in Duobaoshan open-pit mine, the powder factor is 0.60 kg/m³ and the hole row spacing is 7 m×5 m under the conditions that the blast lumpiness is less than 60 cm and the looseness is greater than 1.45 shovel loading.

Rock blastability classification is a prerequisite for determining labour quotas, designing blasting programmes and controlling the unit consumption of explosives. In order to realize a real-time grading of rock explodability, a measurement of in-situ drilling parameters of carbon-bearing muddy dolomite during the excavation process of ore body and roadway in the Shukongping phosphorus mine has been carried out based on the KJ212-1 full-hydraulic boring drilling truck. Combined with the indoor uniaxial compressive strength test, the relationship model between the uniaxial compressive strength R_c and the drilling speed V, the drilling hole diameter D and the rotary pressure M was respectively established and verified. Finally, the model is substituted into the solidity coefficient f relationship equation to derive a model for the relationship between the blasthole drill-following parameters and the rock blastability classification. The results of the study show that the average rate of difference between the uniaxial compressive strength calculated by the relational model and the results of the indoor uniaxial compression tests is 5.5%, which demonstrates the reasonableness of applying the model to the real-time prediction of rock blastability. This model provides a more convenient and fast method for real-time grading prediction of rock blastability. The results show that the dolomitic banded phosphorite, mud banded phosphorite and dense banded phosphorite are medium explosive, carbon-bearing mud dolomite is difficult to explode.

The blasting effect of cut holes has a significant impact on the overall quality of blasting in large section tunnels. To address the challenges associated with difficult excavation and low utilization rate of blast holes, this study employs a fluid structure coupling algorithm based on ANSYS/LS-DYNA to compare and analyze the internal effective force and damage range between single wedge cut blasting and compound wedge cut blasting. The research findings confirm that compound wedge cut blasting yields better results compared to single wedge cut blasting, providing an explanation for this improved performance. The results indicate that in single wedge cutting, peak stress occurs at the bottom of the hole, gradually decreasing from the bottom to the stemming section before dropping sharply from the stemming section to the palm surface. In contrast, double wedge cutting exhibits higher peak stress values at the bottom of the first level cutting hole compared to single wedge cutting. The damage area cross-sections are found to be similar for both types of cutting models. However, in single wedge cutting models, rock from the blockage section to the palm face area remains unbroken and disconnected. Conversely, in compound wedge cutting models, there is complete connectivity throughout the entire groove cavity. Based on these numerical simulation results, an improved blasting scheme was implemented for a specific highway tunnel project. On-site experiments were conducted accordingly. Compound wedge cuts proved more effective in addressing issues such as low utilization rate of blast holes in large section tunnels and multiple large blocks after blasting.

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.

This study aims to analyze the damage evolution law of the surrounding rock mass in an ultra-deep shaft under blasting load. To achieve this, a numerical simulation method is adopted based on the blasting construction practice of Xiling Auxiliary Shaft in Sanshandao Gold Mine. The simulation utilizes a restart technology based on ANSYS/LS-DYNA and adopts the equivalent explosion load method according to the blasting design scheme. The surrounding rock mass damage of the ultra-deep shaft is calculated under four different ground stresses (15 MPa, 30 MPa, 45 MPa, and 60 MPa) and four different side pressure coefficients (1.0, 1.25, 1.5, and 2.0). Furthermore, this study analyzes the damage effect on the shaft's surrounding rock mass and investigates how ground stress and side pressure coefficient influence the extent of damage to the surrounding rock. The numerical results demonstrate that as ground stress increases from 15 MPa to 60 MPa, there is a significant inhibition in the damage area with a decrease in radius from 5.75 m to 3.4 m. Additionally, it is observed that with an increase in lateral pressure coefficient, there is anisotropy in terms of blasting damage area distribution where greater ground stress leads to concentrated damage areas.