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.

With the gradual increase of mining depth, the engineering geological conditions of deep broken surrounding rock mass become complex and changeable, greatly affecting underground projects' construction process and subsequent use period's safety. In order to ensure the safety and quality of deep broken soft rock roadway during the construction process, advanced roof control reinforcement and controlled blasting technology for soft rock roadway were put forward. In view of the characteristics of highly developed fissures and poor stability of rock mass at the No. 6 intersection of-550 m level in Zhongjiu iron mine, it was proposed to adopt advanced roof control measures to strengthen the surrounding rock mass of the roof and improve the bearing capacity of deep-buried broken soft rock roadway. In order to facilitate the excavation construction, 17 excavation areas were divided along the northeast side of the No. 6 intersection, and a four-step method was used for segmented construction. To realize the hole-by-hole shot and reduce the influence of blasting vibration, the detonation interval between two adjacent digital electronic detonators was randomly set to 3~5 ms. According to the overall lithology of different excavation areas, the support methods (pipe shed support, W-shaped steel belt, anchor cable support, etc.) were optimized to ensure the safety of the subsequent use of the No. 6 intersection. The test results show that the advanced roof control reinforcement and controlled partition blasting technology can reduce the roof deflection and subsidence of broken soft rock roadway, which ensures the forming effect of the No. 6 intersection section and reduces the cost of support and shotcrete by 8.7%.

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.

Blasting Engineering is an essential core course for civil engineering and mining majors. To improve the students' understanding on dynamic mechanical response and damage mechanism of rock materials, the experimental teaching contents of explosion and impact dynamics of rock materials were set up in a training plan to achieve the teaching goal of the course of Blasting Engineering. In view of students' lack of theoretical knowledge and experimental basis of impact dynamics in blasting engineering, the split Hopkinson pressure bar (SHPB) experiment technology and two-dimensional plate blasting (TDPB) experiment technology were applied to the practical teaching of Blasting Engineering. Firstly, the experimental system compositions and calculation principles of SHPB and TDPB were introduced. Secondly, the course contents of SHPB impact compression experiment and TDPB central blasting experiment of rock materials were designed. Thirdly, the dynamic mechanical behavior and energy evolution characteristics of sandstone material under the SHPB experiment and the strain wave evolution and dynamic damage and fracture behavior mechanism of sandstone-like material under the TDPB experiment were analyzed. Finally, the students′ in-depth discussion on the critical problems of rock impact dynamics was guided. The innovative combination of SEM testing technology and impact dynamics experimental technology revealed the damage mechanism of rock materials under SHPB and TDPB experiments to students from the micro-level, which gave the students a clear understanding of meso-damage and macro-failure. The effect of teaching practice shows that the student's theoretical and practical ability is exercised by combining the experimental course of SHPB and TDPB with the theoretical course of Blasting Engineering, which leads to the improvement of students' scientific research ability and the sense of teamwork, and the fulfillment of the teaching goals.

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.

To reduce the loss and dilution of ore in Husab Mine, a blasting movement monitoring (BMM) system was introduced and tested in three production blocks with 177 mm diameter drilling holes and a 7.5 m step height. During the field test, 6, 8, and 5 monitoring holes were arranged in each test block. Two displacement monitoring balls were placed in each monitoring hole at a 3.5 m and 9m depth to record the rock body's vertical and horizontal movement after blasting. The results show that the movement of the ore body due to blasting can be detected by BMM, and the average horizontal displacement of the upper ore body of the three test blocks is 6.55 m, 6.97 m, and 9.24 m, respectively. The average horizontal displacement of the lower ore body is 3.2 m, 3.9 m, and 4.0 m, respectively. The average vertical displacement of the upper ore body is 4.1 m, 2.0 m, and 3.2 m, respectively. The average vertical displacement of the bottom ore body is 0.72 m, 0.98 m, and 0.84 m, respectively. The ore body always moves in the direction with the least resistance during blasting. Whether horizontal or vertical displacement, the displacement of the upper ore body is always more significant than that of the lower ore body. In addition to changes in the boundaries between the ore and rock due to horizontal displacement, vertical displacement also has a significant influence on the loss and dilution of ore, and the bottom ore body may also move to the middle or the upper part of the ore body, and vice versa. The blast zone of open pit mines often consists of a variety of rocks, and both horizontal and vertical displacements of the ore body after completing the blast design based on geological information are the leading causes of ore grade reduction. Using the post-blast rock boundaries obtained from the BMM system monitoring to guide the excavation and transportation operations, the average ore dilution rate has been reduced by 1.2%. The average loss rate has been reduced by 1.5%, which can create more than 10 million RMB of economic benefits cumulatively over the entire life of the Husab Uranium Mine. This technology can accurately define the ore-rock boundary after blasts, which is an important technical means to reduce the ore dilution rate, ore loss rate and ore grade classification errors in open pit mines.

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.

Husab Uranium Mine is a super-large-scale open-pit uranium mine. Currently, the mine adopts a “one-time design, long-term use” approach to blasting production, leading to issues such as a lack of dynamic adjustment of blasting parameters, high explosive consumption, and unsatisfactory blasting results. To address these issues, a solution can be achieved through dynamic blastability classification management of blasting blocks and feedbackcontrolled blast design. This study utilizes the production history big data of the mine's blasting blocks. It proposes a method to calculate the blasting index K using drilling rate (α), explosive consumption per unit volume (β), and fragmentation index (γ). Here, α represents the drill hole cross-sectional area per unit area, where a higher value indicates more drilling required and higher drilling costs. β represents the amount of explosives required per unit volume of crushed rock, where a higher value implies a more significant amount of explosives required and higher blasting costs. γ represents the distribution of fragment size after ore blasting, where a higher value indicates worse blasting effects, higher transportation costs, and greater difficulty in blasting. Based on the value of the blasting index K, the blastability of historical blasting blocks is classified into different levels. Uniaxial compressive strength (UCS) of the blasting blocks, rock quality designation (RQD) of the ore, and geological strength index (GSI) of the ore deposit are used as blastability indicators, establishing a dataset correlating blastability indicators with blastability levels. The dataset consists of 69 sets of historical data, with 20 sets classified as level one (easily blastable), 24 sets as level two (relatively difficult to blast), and 25 sets as level three (difficult to blast). Subsequently, a deep learning neural network model is constructed, comprising an input layer, five hidden layers, a dropout layer, and an output layer. The model is trained using blastability indicators as inputs and blastability levels as outputs. The traditional SVM model is used for comparison, revealing that the trained deep learning neural network model achieves higher prediction accuracy on the test set than the traditional SVM model. Finally, the reliability and accuracy of the trained deep learning neural network model in predicting the blastability level of blasting blocks are verified through on-site experiments, optimizing the blast design and blasting effects. The research findings indicate that the trained deep learning neural network model, based on a large amount of historical production data from Husab Uranium Mine, can be used for blastability classification of blasting blocks and optimization of blasting effects.

To control the height and recoil distance of a frame-shear wall structure after demolition by blasting, a frame-shear wall residential building demolition project in Qingdao was chosen as the subject. The simulation analysis used ANSYS/LS-DYNA software and the orthogonal combination of collapse angle and crotch extension time difference. Firstly, a finite element model of the original scheme was built, and the model's validity was checked by comparing the variance between the model prediction and actual outcomes. Then, the trends of the structure recoil distance and burst pile height with the change were analyzed by changing simply the model's inter-span extension time difference and cut height. Furthermore, the semi-quantitative formulas for the relationships between recoil distance and burst height with notch height and inter-span delay time difference were proposed based on the outcomes of multi-scenario numerical simulation, which were allowed for the determination of the inter-span delay time difference and notch height for the cases of minimum structural recoil distance and burst height, respectively. Finally, the analysis was carried out on the acceptable span-to-span extension time difference and the range of blasting notch heights for demolition blasting of frame-shear wall structures. The results show four fundamental steps to the collapse of frameshear wall structures: blast notch creation, destabilized overturning, notch closure, and landing collapse. The study's findings indicate that the recoil distance of each model primarily increases at first and then decreases as the interspan extension of the blast section is prolonged at the same cut height. Meanwhile, there is a more significant disparity in the structure's recoil distance as the deferred time difference is extended, and the recoil distance increases with the height of the blast cut at the same inter-span extension. Additionally, the height of the detonation pile roughly decreases as the time lag increases. The shear walls simultaneously improve the structural integrity and prevent the building from collapsing during the collapse, resulting in better structural integrity after collapse. The structure reduces recoil distance when employing a short incision height and a 200 ms extension time difference. The most minor burst heights of the structures are those with considerable notch heights and a 300 ms delay time difference. A crotch delay time difference of between 270 and 420 milliseconds is adequate. More importantly, a large blast cut can lower the pile's height, while a tiny blast cut can effectively regulate the recoil. It can be reasonably chosen based on the demands of the area around the structure that will be torn down. The study can provide a guide for determining the incision height and delay time difference for demolishing frame-shear wall structures by blasting.