The multi-body and discrete-body dynamic analysis of demolished reinforced concrete structures in China is based on the multi-body dynamic equation (symbol, function) and the variable mass collapse dynamic equation, and the comprehensive solution of the equation, including an analytical solution, is obtained. Using close-range photogrammetry and dynamic equation inversion, the plastic dynamic and structural dismantling parameters of damaged reinforced concrete materials are obtained. Based on the similarity criterion of dynamic equations solution, similarity criterion formulas of notch for different collapse modes of Various structures are established. Namely, the similarity criterion curve fitting formula (5), it's another formula (6), empirical formula (7) of single-notch for building toppling, the example modification curve C₄ of similarity criterion of inter-span falling, and the forward. Toppling similarity criterion formula (8) of backward-seated buildings with the single notch, the similarity criterion formula (9) of continuous impact collapse between floors of high-rise buildings, the empirical formula (10) of multi-notch in-situ impact collapse of high-rise buildings, the overturning similarity criterion curve of double-notch buildings in the same direction, and other notch-similarity criterion curve families of building structure collapse, etc. Furthermore, the building collapse rules of the demolition matching table of building structure-collapse mode-notch characteristics are put forward by analogy with 46 demolition examples from its notch similarity criterion curve and example diagram in China. The judgment rules of building collapse are determined when the coordinate points [λ (λ₁, λ_p), η_h (η_r)] of the building structure and the incision are near the top of the similarity criterion curve. The cut size of various demolition methods of different building structures can be easily determined, and dimensionless charts can determine the demolition effects. Therefore, a simple and accurate demolition control of blasting demolition can be realized using the multi-body dynamic incision control demolition technology (MBDC).

Dynamic mechanical tests were carried out on EPS concrete at early ages (12 h、24 h and 36 h). Whereafter, the influences of impact velocity (4.5~6.5 m/s) and age (12 h、24 h and 36 h) on impact resistance of EPS concrete were analyzed in terms of dynamic compressive strength, peak strain, ultimate strain and energy dissipation density. Additionally, the properties of EPS concrete at early ages were compared with that at the age of 28 d. The results show that the dynamic compressive strength, peak strain, ultimate strain, and energy dissipation density of EPS concrete have an impact on the velocity-strengthening effect. With the increase of age, the dynamic mechanical property indicators of EPS concrete and its sensitivity to impact velocity increase. At the age of 28 d, the dynamic compressive strength, peak strain, ultimate strain and dissipation density of EPS concrete are the maximum, and its sensitivity to impact velocity is the strongest. EPS concrete has good deformation and energy absorption characteristics at the early age. At the age of 36 h, the peak strain, ultimate strain and energy dissipation density of EPS concrete can reach 66%~82%, 91%~93% and 72%~78% of that at the age of 28 d, respectively.

In view of larger holes and higher density operators with the traditional blasting of packed explosives, this paper launched 60 on-site blasting experiments in a plateau tunnel. The charging efficiency of different numbers of exploders was summarized, the hole network parameters were optimized and smooth blasting effect of peripheral holes were improved. Compared with the smooth blasting effect, the number of holes dropped from 151 to 124. The spacing of peripheral holes was gradually optimized from 45 cm to 60 cm based on the advantages of good mechanical and coupling charging on-site mixed explosives. The result shows that the on-site mixed loading blasting in plateau tunnel can improve more than 40% efficiency per operator and reduce 90% of labor intensity compared with the traditional blasting of packed explosives. It can significantly reduce the number of operators and improve the efficiency of drilling and loading, saving more than 15% of drilling quantity and explosive equipment. Lastly, more than 3% of the utilization of circular footage has been improved, which shows that on-site mixed-loading blasting can accelerate construction progress.

When conducting blasting under deep water, the explosive will be affected by high water pressure and long-term water immersion conditions due to the long charging time. Only when the performance of the explosive meets the technical requirements can the blasting effect be guaranteed. Taking the waterway regulation project of Liantuo river between the Three Gorges Dam and Gezhouba Dam as the research background, it was found the original emulsion explosives composition was weak in resisting deep water pressure during the reef blasting. The detonation distance was small, and the intensity was insufficient during the construction at a depth of 40 m. The performance of water gel explosives, chemical-sensitized explosives, glass microsphere-sensitized explosives, and perlite-sensitized explosives were studied by experiments in the laboratory adjusted the hydrostatic surface pressure to simulate the deep-water condition by using the deep-water measurement method. A relationship between the explosive performance and immersion time was explored under different water depth conditions. Meanwhile, a relationship between the explosive performance and water depth was built under different immersion time conditions. Comparing the experimental results, the study shows that the performance of glass microsphere-sensitized explosives, chemical-sensitized explosives, perlite-sensitized explosives, and water gel explosives all slightly decrease and meet the engineering requirements when the water depth is 0~20 m. It is recommended to use glass microsphere-sensitized explosives and perlite-sensitized explosives when the water depth is 20~40 m, and the glass microsphere-sensitized explosives are suitable when the water depth is 40~50 m. Besides, the glass microsphere-sensitized explosives have relatively small performance degradation under high pressure and long-term immersion conditions, and it is suitable for underwater drilling and blasting construction in deep water conditions.

Field tests in a region of the plateau were carried out to study the “poly device+emulsion explosives” in tunnel surface blasting and to achieve the feasibility of peripheral hole air spacing charge and poly device on the explosives detonation distance. A seamless steel tube was used to simulate the tunnel peripheral hole for two or more sections of “emulsion explosives+poly device” detonation. A martyrdom test was implemented with#2 rock emulsion explosives. The maximum stable detonation and martyrdom distance were obtained through several groups of experiments. The test results show that the maximum stable detonation and martyrdom distance 15 cm length of polymerized explosives and#2 rock emulsion explosives are respectively 230 cm and 115 cm in the seamless steel tube. The maximum stable detonation distance of multi-section polymerized explosives can reach 80 cm. Due to the radial constraints on the detonation wave of the polymerization device, the front end of the conical metal drug mask explosion formed by the polymerization of energy jets significantly increases the axial and upward shockwave energy, which makes it possible to increase the energy of the shockwave. The emulsion explosives in seamless steel pipe detonation distance increased significantly upward shock wave energy, which can be applied to the tunnel perimeter hole, replacing the detonating cord to achieve air spacing charge and enhance the effect of surface blasting, cost savings, and time savings.

To study the effect of aluminum powder particle size on the performance of CO₂ phase change explosion exciters, the changes in the thermal decomposition characteristics, safety, temperature resistance, and reaction heat were investigated by the calorimetric method (TG), ignition test, temperature resistance test, and reaction heat test. The results show that the thermal decomposition characteristics of the excitation agent did not change significantly after adding 40、80 and 120 μm aluminum powders. However, the apparent activation energy of the activator was significantly different. The apparent activation energy of the excitation agent containing 40 μm aluminum powder decreased by 52.92 kJ/mol. Still, the apparent activation energy of the excitation agent containing 80 μm and 120 μm aluminum powders increased by 55.21 and 57.53 kJ/mol, respectively. After adding different particle sizes of aluminum powder, each sample can be ignited in the air, and the combustion process is accompanied by white smoke. A-mong them, the excitation agent with 120μm aluminum powder burns more violently than that without aluminum powder and that with 40 and 80μm aluminum powder. The experimental results show that the excitation agents containing different particle sizes of aluminum powder can be excited by the electric primer, but the sample is not completely ignited. When these excitation agents are in a closed environment and under a certain pressure (greater than or equal to 0.2 MPa), they can be reliably ignited without an obvious explosion phenomenon, indicating that their safety is good. After holding at 70℃for 48 h, the overall excitation agent added with aluminum powder did not change significantly, and the temperature index T_s was about 70℃, indicating that its temperature resistance was good. When the mass percentage of aluminum powder with different particle sizes is the same, the increase in reaction heat is about 12%, indicating that the particle size has little effect on the reaction heat of the excitation agents.

Rock drilling and blasting inevitably produce blasting vibration effects and hazards. The accurate analysis and prediction of blasting vibrations and effective active control methods are thus of great practical significance. This paper summarises the achievements in the prediction and active control of blast vibration velocities over the past 40 years. In terms of predicting the peak value of the blasting vibration velocity (PPV), empirical model prediction methods are very convenient, but their prediction accuracy and effectiveness are poor. By introducing probability and statistical theory into empirical model prediction methods, the accuracy of PPV predictions can be improved. The fundamental wave superposition prediction method can comprehensively predict the vibration velocity, frequency, and duration. However, this method requires high testing accuracy for fundamental vibration waves, which requires the establishment of a regular calibration and verification mechanism for blasting vibration data acquisition devices in the blasting industry. Artificial intelligence prediction methods can significantly improve the accuracy of PPV predictions and provide new ideas for predicting blasting vibration effects under the influence of multiple factors. However, these methods are all based on massive amounts of real and effective measured data, and a substantial database of vibration testing data samples is currently lacking. Theoretical PPV prediction models and numerical simulation prediction methods have also been proposed. However, the widespread application of these methods in engineering practice is limited owing to the requirements for professional knowledge and numerical simulation technology. In terms of the active control of blasting vibration velocity, reasonable delay time determination methods for reducing the PPV are first discussed based on the superposition interference effect of vibration waveforms. However, the recommended delay time values proposed by most current methods are only suitable for protecting a single target structure. Then, a method for actively changing the delay time to regulate the frequency components of blasting vibration is discussed from the perspective of adjusting the spectral structure of blasting vibration, which can avoid the natural vibration frequency band and reduce blast vibration hazards to buildings (structures). However, this method currently remains at the theoretical level or under model experimental-scale conditions and lacks large-scale on-site application examples for verification. Finally, several key future research directions for the prediction and control of blasting vibrations are discussed.

To accurately predict the peak particle velocity (PPV) and effectively reduce the hazards of blasting vibration, a prediction model was built by BP neural network based on the blasting project of Xingguang No. 1 openpit mine. Seven influencing factors as core distance, plugging length, minimum resistance line, explosives unit consumption, maximum single-hole charge, total extension time, and maximum single-delay charge, were selected as input variables, and the correlation between each factor and PPV was evaluated by using the grey correlation analysis method. The Sparrow Search Algorithm (SSA) optimized the BP neural network to predict the three-way peak vibration velocity. By comparing and analyzing the prediction results of the BP neural network model, the average errors of the prediction results of the SSA-BP neural network model were 6.08%, 7.34%, and 1.91%, respectively, and that of the prediction results of the BP neural network model was 22.19%, 54.01%, and 25.29%, respectively. The results show that the SSA-BP neural network model comprehensively considers the influence of multiple blasting design parameters on the peak vibration velocity. The sparrow search optimization algorithm can effectively solve the problem of the traditional BP neural network model, which quickly falls into the local optimum. The prediction results are more accurate, and the vibration velocity monitoring value is more consistent with smaller errors. Meanwhile, it can significantly shorten the learning and training time of the sample data to speed up the convergence speed of BP. Additionally, it can also significantly shorten the training time of sample data and accelerate the convergence speed of the BP neural network prediction model.

The blasting dynamic response of the gas pipeline and surrounding soil during the excavation of the cross passage at the entrance and exit C of Jinding Street Station of Beijing Metro Line 11 was analyzed using the finite software LS-DYNA. The numerical model's accuracy was confirmed by comparing it with blast-induced vibration data from on-site surveys. The study focused on the dynamic response of the buried gas pipeline to tunnel blasting, considering factors such as different cutting hole delay times, single hole charge, and soil properties. The results indicated that the peak particle velocity (PPV) from the numerical model was within 20% of the field test data. The PPV and peak effective stress (PES) of the pipeline were highest at the side back of the explosion source. A linear relationship between PPV values of the surface soil and the pipeline was observed when the horizontal distance from the tunnel center exceeded 3m in the axial direction of the gas pipeline. The PPVs and PESs on the cross-section of the gas pipeline did not change significantly with increasing delay times between cutting holes. Furthermore, increasing the charge of the cutting hole from 0.2 kg to 0.6 kg led to an increase of 0.5~2.5 times in PPVs and 0.5~1.5 times in PESs. The soil type around the gas pipeline also influenced the peak combined vibration velocity and effective stress, with silty clay having the greatest impact, followed by clayey silt, and then miscellaneous soil.

Although the rock stratum can be blasted into blocks in advance on the ground when the shield machine bores through silt-rock strata, the vibrations generated by blasting in silt-rock strata will threaten the safety of the water supply pipeline near the blast area. Based on the blasting vibrations of field tests and numerical simulations, the physical and mechanical parameters of the materials on sites were verified, and the dynamic response of the water supply pipeline near the blast area was studied. The research results show that the peak particle velocity (PPV) decreases with the increase of the horizontal distance from the explosion source on the pipeline along the axial direction. The PPV also decreases with the increase of the horizontal distance from the explosion source on the ground surface above the pipeline along the axial direction, and there is a relationship between the PPVs of the pipeline and the PPVs of the ground surface above the pipeline. The maximum PPV of the pipeline's inner wall is 3.97 times the minimum PPV, and the PPV is the highest at 90° of the inner wall. Meanwhile, the maximum PPV of the pipeline's outer wall is 1.03 times the minimum PPV, and the PPV is the highest at 150° of the outer wall. Besides, the PPV of each node is different from that of the other, and the PPV on the pipeline's inner wall is more significant than that on the pipeline's outer wall. Although the PPV on the pipeline's inner wall changes significantly, the PPV on the pipeline's outer wall is relatively close. The maximum peak effective stress of the element is 4.06 times the minimum peak effective stress of the element, and the peak effective stress of the element is the highest at 240°~270° of the pipeline's outer wall.