The peak particle velocity (PPV) of blasting vibration is an important index to measure the impact of blasting vibration on surrounding environment and structures. In order to improve the reliability of PPV prediction, a model based on extreme gradient boosting optimized by the sparrow search algorithm was proposed, and a corresponding blasting vibration prediction system was built using the App Designer of MATLAB. The maximum charge per delay, distance from blast center to measuring point, and elevation difference between measuring point and blast center were selected as the input parameters of 36 sets of training data and 5 sets of test data for the model to predict PPV. The results show that the proposed SSA-XGBoost model has a smaller average relative error compared with the GA-BPNN model and BPNN model, and it has a higher prediction accuracy and better stability proved by the Taylor graph.

A kind of explosive stemming apparatus with detonating cord was placed in a simulated blast hole to evaluate its blocking effect, and then a uniaxial compression test was performed on it using a universal testing machine. The result showed that the compressive strength of the explosive stemming apparatus after being in contact with the blast hole wall was 26.5~35 MPa, and the shear strength was 3.07~3.4 MPa, which was much higher than the shear strength of conventional stemming materials (0.09 MPa). The explosive stemming apparatus was applied on cut blast in tunnel excavation together with optimizing the original blast hole layout. It turned out that the number of cut holes reduced by 35% compared to before optimization while maintaining the same excavation depth, and the hole spacing increased accordingly, which reduced the risk of piercing adjacent cut holes and effectively improved construction efficiency. Therefore, combining the explosive stemming apparatus with stemming material can greatly enhance the blocking effect and prevent premature gas escape. This effect can further extend the gas action duration in the blast hole, and improve the throwing effect of explosion gases by fully exerting the gas wedge rock breaking effect.

In view of the problem of noise and information loss in the CEEMDAN method in the denoising process of actual measurement blasting vibration signals, the clustering analysis method is considered to have good data processing ability. Based on the idea of decomposition-clustering-reconstruction, CEEMDAN-K-means algorithm for denoising of blasting vibration signals is proposed. Firstly, this method decomposes the blasting vibration signal by CEEMDAN method to obtain IMF components of different quantity levels. Then, the K-means clustering analysis algorithm is used to classify the IMF components into five different categories, and variance contribution rate verification is used. Finally, the IMF components of high frequency noise category are removed and the reconstructed pure blasting vibration signal is obtained. Taking the blasting vibration signals from an open-pit mine as example, the signal denoising performance of the CEEMDAN-K-means algorithm was evaluated by signal-to-noise ratio and root mean square error indexes. The research results show that compared with the CEEMDAN method and the EMD-wavelet threshold method, the CEEMDAN-K-means signal denoising method has the largest signal-to-noise ratio (20.06 dB), which is increased by 1.26 dB and 7.7 dB, respectively, and the smallest root mean square error (0.22 10^-3), indicating that the method not only has good denoising effect, but also has good fidelity. Through the comparison and analysis of the denoising effect of different methods, it is known that on the basis of effectively retaining the real signal component, the CEEMDAN-K-means method can effectively remove the high-frequency components contained in the measured blasting vibration signal, and has practicality and effectiveness in the field of blasting vibration signal denoising.

To study the influence of different geo-stress levels on the propagation of explosive stress waves in natural environment such as mountains and dams, numerical simulation technology was used to simulate the explosion of concrete specimens under different geo-stress conditions. First, by applying different stresses to the boundary of the concrete specimens, the failure of specimens subjected to explosive load were observed. And then, the peak stress and particle velocity of the four preset measuring points on the specimen were obtained by changing the unilateral ground stress value and keeping the same explosion load on different models. Finally, the influence of geo-stress on the propagation of explosion stress wave was analyzed on different characteristic parameters of explosion wave, such as the peak stress and particle velocity. The results show that the influence of geo-stress on explosion stress wave is mainly manifested as “restraining propagation” and “promoting propagation” under high and low stress level, respectively. During the explosion process, the superposition coupling of explosion stress wave and in-situ stress increases the peak stress intensity of the measuring point. On the contrary, the high ground stress inhibits the displacement of the medium particles, thereby reducing the particle velocity. The research starts from the influence of different ground stress levels on the propagation of explosive stress waves, and creatively analyzes the inhibition of ground stress on stress waves.

In the process of tunnel blasting excavation, the influence of ground stress and joints on the blasting effect of rock mass is significant, and they are two important factors that must be considered in the layout of tunnel blasting holes. The static and dynamic mechanical parameters of jointed slate were obtained by indoor experiments by taking the Tongan Expressway Bayue Mountain Tunnel as the engineering background. Based on the LS-PREPOST software, a three-dimensional numerical model of jointed rock mass tunnel blasting under different ground stresses (3 MPa, 6 MPa, and 9 MPa) was established to analyze the distribution of effective stress at different locations after blasting. A method for the layout of blasting hole network in jointed rock mass tunnel under different ground stresses was proposed, and the method was verified based on on-site blasting experiments. The results show that ground stress has a restraining effect on crack propagation during jointed rock mass tunnel blasting, and the greater the ground stress, the more obvious the restraining effect. The explosion stress wave will undergo multiple refractions and reflections at the joint location, leading to serious over-excavation. When the hole spacing of the contour holes in the grade IV rock mass was set to 45 cm and the linear charge density was set to 0.375 kg/m, the average over-excavation value was controlled within 20 cm. The designed concrete volume of the research section was 15.1 m³, and the actual concrete consumption in the three on-site tests was 26.4 m³, 23.7 m³, and 25.8 m³, with an average concrete excess consumption of 10.2 m³ and an average excess consumption rate of 67.5%, which were all controlled within 100%.

The charge parameters are crucial factors affecting the damage effect of RC components under close-in explosion. The study of the influence law of different charge parameters on component damage is of guiding significance for improving warhead design and optimizing fire strike scheme. A cylindrical charge with a length to diameter ratio of 5.5 and a charge of 10 kg was used to carry out near explosion damage tests of the supporting column of a reinforced concrete single-storey stacked structure plant at a proportional distance of , and a comparison test of spherical charge was set up. The experimental results show that the damage effect of a cylindrical charge is stronger than that of a spherical charge, and the reliability of the numerical simulation model is verified by the experimental data. The length to diameter ratio, blast height, charge amount and action distance of cylindrical charge are taken as the research factors, and three levels are determined for each factor. The simulation results of blast damage of reinforced concrete under 9 different charging parameters were designed and obtained by orthogonal simulation test method, and the influence law of cylindrical charging parameters on the damage effect of reinforced concrete columns was analyzed. The amount of the cylindrical charge has the greatest effect on the damage degree, the ratio of length to diameter has the second effect, and the blast height has the least effect on the damage degree. When 4.5≤L/D≤6.5, the damage effect on the component is greater. When the blast height is 1/4, 1/2 and 3/4 column height respectively, the explosion at the 1/4 column height has the best damage effect on the support column.

The estimation of equivalent and depth of underwater explosions is an important task of the hydroacoustic monitoring in the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). In order to effectively estimate the equivalent and depth of underwater explosion in near and far-fields, the relationship between the ratio of the first and second periods of the bubble pulsation and the bubble radius and depth was fully used based on the semi empirical formula of bubble pulsation period. The analysis results of near-field underwater explosion show that the average estimated equivalent and depth are about 118 g and 7.96 m, 76 g and 21.4 m, 1.23 kg and 44 m for different actual TNT equivalent values and blasting depths of 100 g and 7 m, 100 g and 25 m, 1 kg and 50 m, respectively. These results show that the depth estimation is more accurate than the equivalent estimation. Furthermore, the proposed method failed for a small explosion equivalent of 100 g and a depth of 50 m, which indicates that the method is limited in explosion depth. Finally, this method was used to analyze the far-field underwater explosions recorded by IMS hydroacoustic stations, and the equivalent and depth estimation results were consistent with the references, which indicated that this method is also suitable for the far-field explosion estimation.

During open-pit bench blasting, the movement trajectory of rock in the bench area is an important factor affecting the accurate mining of open-pit mines, especially for unevenly mineralized ore bodies. In order to solve the difficult problem that the internal movement trajectory of rock during bench blasting in the Wushan Cu-Mo mine is not clear, a tracking algorithm with signal markers was used on bench blasting tests at the Wushan Cu-Mo mine in Manzhouli. Through on-site installation, positioning, monitoring and data analysis of intelligent beacons, the research results showed that: the first row of beacons had a long motion time and fast movement with an average speed of 5.89.8 m/s. The movement distance was between 18.4 m and 29.4 m. Due to constraints and obstruction of the rock mass in the front section of the bench, the motion time, movement speed and distance of the#2 monitoring beacon were significantly reduced, with an average speed of 1.8~4.8 m/s and a movement distance of 5.3~14.2 m. The movement distance and time of the#3 blast hole beacon was the smallest, and the inclination angle of the#3-3 beacon reached about 25°. The inclination angles of#6-1, #6-2 and#6-3 beacons were relatively gentle at about 2°~8°. From the depth perspective, the shallow beacons move forward horizontally during the forward rush period, and there was a significant downward trend in the latter half. The vertical motion distance of the deep beacons was significantly smaller than that of the shallow beacons.

In order to control the forming effect of excavation profile and reduce the disturbance of preserving rock mass caused by blasting, the foundation pit blasting at the Yunnan bank of the large arch bridge across Jinsha river, whose total depth is about 51 m and one-time excavation depth is about 20 m, is taken as the engineering background. Reinforced loose blasting with hole-by-hole initiation was applied to the main blasting holes and smooth blasting was used for the contour holes. A kind of deep hole smooth blasting technology which can be applied to foundation pit excavation of the deep and steep arch bridge is presented. In addition, the action process of gas, the expansion pressure at the hole wall and the damage range of the smooth blasting hole were theoretically calculated and analyzed. The blasting results show that a flat excavation profile, with more than 90% half-hole ratio of relatively intact rock mass and less reserved hole marks of relatively cracked rock mass whose overbreak and underbreak can still be controlled, can be formed by using the deep hole smooth blasting technology, which greatly reduces the stress concentration on the rock wall surface. The crushing zone will not be formed near the charge section in the smooth blasting and the maximum damage range of the reserved rock mass was about 49cm, which fully ensured the rock wall stability and construction safety. In the process of smooth blasting construction, engineering measures were also taken to ensure the reliability, safety and economy, including slowly tilting the excavation surface at the bottom of the bench to the free surface, tying the explosive charge with cotton rope for traction, and setting detonators inside and outside the hole every 5~7 smooth blast holes.

In the field of blasting work, stemming has a significant impact on the effectiveness and safety of blasting operations. To improve the blasting effect and reduce blasting costs, it is essential to determine the optimal length of stemming. This study uses a combination of explosion wave theory, theoretical mechanics, and LS-DYNA numerical simulation to analyze the impact of stemming length on blasting effect, which is then validated through field experiments. The study results indicate that when the blast hole depth is between 0.6 m and 1.4 m, the optimal stemming ratio is between 0.38 and 0.54, and with an increase in blast hole depth, the optimal ratio decreases. When the blast hole depth is between 1.6 m and 2.4 m, the optimal stemming ratio is between 0.36 and 0.38. If the blast hole depth exceeds 1.2 m, and the stemming length equals or exceeds half of the blast hole depth, a detrimental effect may occur. The radial uncoupling coefficient R exerts a significant effect on the optimal stemming length. When R is less than or equal to 1.8, the optimal stemming length decreases with an increase in R. However, when R is greater than 1.8, the optimal stemming length remains unchanged. Additionally, field experiments were conducted at the Wangcun Coal Mine Limited Liability Company 8107 return airway, including tests on 1.2 m and 2.2 m cut holes and a 2.0 m auxiliary hole. The optimal stemming lengths were found to be 50 cm, 90 cm, and 80 cm, respectively, which aligns with the results of theoretical calculation and numerical simulation.