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.

A combined demolition method of directional tilting of main tower and in-situ collapse of bridge beam has been designed for the blasting demolition of a single-tower reinforced concrete cable-stayed bridge in complex environment. An "inverted step" cut with a height of 4 m was designed for the middle tower pillar, and the mechanical pre-processing method was used in the lower tower pillar to form two windows with a width of 1.3 m and a height of 4 m to reduce its strength. The loose blasting was used for the bridge beam at four locations where the cables were anchored on the beam. Decked charge was adopted for the blast holes deeper than 2.1 m and initiated by detonating cords, which effectively dispersed the explosive energy. The middle tower pillar, lower tower pillar and the beam were initiated as 3 stages with nonel detonators. A “rigid + flexible” composite protection method was proposed for the culvert crossing the bridge. Two sandbag damping walls were settled on the touchdown area of the bridge beam to form a "flexible" protection. Meanwhile, a welded steel skeleton and rubber cushion layer were arranged along the direction of the culvert to form the “rigid” protection. Grass curtains, bamboo fences, and steel wire layers were covered on the blasting area. After the blast, the tower toppled on the predetermined direction. And the main beam collapsed in place, divided into several sections which were then processed with mechanical methods. In this project, good blasting results have been achieved without causing flyrock accidents or impact damage to the culvert.

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.

Underwater blasting tests are dangerous and costly. The requirements for the related test equipment and site in laboratory are very strict. Each test must be approved in accordance with relevant procedures. In view of the current situation of cumbersome blasting test procedures and long waiting periods, a wave barrier curtain which can achieve satisfactory results with as few underwater blasting tests was designed by using collision and vibration simulation technology. In order to achieve this purpose, the protection of wave barriers made of different materials were simulated by the ANSYS LS-DYNA module. Data were collected at a position 5 m away from the explosion point with a pressure of 7.5 MPa, and the detonation wave reduction coefficients of the canvas wave blocking curtain and other five different materials were compared and analyzed. The simulation results showed that the wave resistance performance in order from high to low is: air bubble, porous aluminum plate, automobile tire, foamed plastic, asbestos cloth. Among them, under the equivalent working condition of 1 kg TNT, and at the location 5 m away from the explosion point with a pressure of 0.22 MPa, the air bubble's pressure reduction rate reached 97%, and the protection effect was the best.

Based on the actual production in jilangde open pit coal mine, the application of air interval charging blasting technology was clarified, defining two test significance: one is “reducing cost and increasing efficiency”, the other is “controlling blasting fragmentation”. Three groups of orthogonal tests are used to evaluate the application effect of air interval blasting technology. The photo photography method is used to identify the fragmentation distribution after blasting. Firstly, the matlab program is optimized with reference to relevant literature to process the fragmentation image into fragmentation distribution data. Secondly, the data is imported into Origin software to generate fragmentation distribution curve to evaluate the blasting effect. The test results show that the fragment size distribution of 17.3% interval blasting is close to continuous charging blasting. Conclusions 1: The air interval height has no positive correlation with the final effect., There is a reasonable interval height which is in line with the purpose of reducing cost and increasing efficiency of enterprises. The fragmentation grading evaluation method is used to analyze the uniformity of blasting effects of different charges. Firstly, the fragmentation distribution data is imported into Origin software to fit the blasting fragmentation grading curve. Secondly, five fragmentation evaluation indexes are summarized with reference to relevant literature. The analysis results are the uniformity of blasting block: continuous charge > interval 17.3% > interval 11.5% Conclusion 2: The charging amount can be reduced through the control of central air interval charging technology, so that the blasting effect is close to the traditional continuous charging, which can achieve the purpose of controlling blasting fragmentation.

The average lumpiness of ore rock is an important index to measure the blasting quality. The early research mainly relies on empirical formula summary, rock mechanics model calculation, which have shortcomings such as insufficient accuracy and strong subjectivity. Recently,, machine learning algorithm is applied for prediction, but still have problems such as empirical feature selection, insufficient model prediction stability, and poor generalization ability for the prediction of blasting material fragmentation. Aiming at above shortcomings, an extreme Gradient Boosting (xgboost) blasting fragmentation prediction model based on Feature Engineering is proposed. Taking Yuanjiacun Iron Mine in Taiyuan as the research area, engineering data are collected, Random Forest (RF) and Mutual Information (MI) are used for feature selection respectively, and the two feature subsets are integrated to obtain the best feature subset based on the value of MSE. XGBoost is used to predict the block size on the optimal feature subset, and the evaluation system is composed of two indexes: Mean Square Error (MSE) and Mean Absolute Error (MAE). The proposed method is compared with other traditional machine learning algorithms, and the results show that it is better than others. Furthermore, it can provide scientific guidance for the management and control of blasting.

The Yan Zhou power station bridge was built on the proposed structure site of the Yan Zhou hub project, which included construction of a new ship lock, power station, and spillway gate. Due to the progress of the engineering construction, the bridge was dismantled. The Yan Zhou power station bridge is a hyperbolic arch bridge with a total length of 180.0 m and a width of 8 m. It is located in the Pengshan tourist scenic area, surrounded by many famous historical sites and enterprise factories. The environment was complex, and the nearest distance from the bridge to the existing power station dam was 8 m. The reinforced concrete box girder bridge of the power station dam was adjacent and shared a bridge pier with it. Due to the working conditions on-site, blasting demolition was adopted. In order to ensure the reliable collapse and complete disassembly of the entire bridge, as well as the separation of steel bars and concrete, the components such as arch ribs, arch columns, and connecting beams were pulverized through throwing explosive devices, with a powder factor of 1.2~1.5 kg/m. Reinforced loose blasting was used to destroy the bridge piers, and the maximum explosive charge for a single pier was 480 kg. According to the principle of heavy left and light right, the entire bridge was collapsed toward the right bank direction like a domino. An inner-hole delay and out-hole relay initiation network was used. The MS12 detonator was used for the inner-hole delay, and the industrial electronic detonators were used in parallel out of the holes. The blasting order was from left bank to right bank, and then from pier to pier, to ensure that the bridge collapsed orderly and vertically, without causing crushing impact to the left bank bridge pier. A leaky PVC was pre-laid underwater along a 100m line near the left bank power station and water roller dam. An air compressor was used to press the air into the pipe to form an air bubble curtain, which effectively reduced the water shock wave overpressure, thereby reducing the impact of blasting vibration and water shock waves on surrounding buildings and structures.

The study of damage expansion process of the surrounding rock mass under blasting is of great significance to the blast resistance design of a chamber. In order to explore the damage propagation law of the surrounding rock mass around a chamber under the action of different blasting sources, a numerical calculation model including top explosion, vault side explosion, side wall explosion, bottom side explosion and bottom explosion was established by using the finite element simulation software ANSYS/LS-DYNA. The RHT model was used to analyze the damage propagation process of the chamber surrounding rock mass at different positions. On this basis, 10 vibration velocity monitoring points were set equidistantly from the blast source to the chamber boundary in the model, and the vibration velocity attenuation law from the blast source center to the chamber boundary was studied. The results show the damage point first appears at the shortest distance from the blast source, and is then formed subsequently. The damage zone expands gradually along the boundary of the chamber and finally forms the damage zone. Compared with the decay law of the blasting vibration velocity, the blasting vibration wave is fully reflected in the surrounding rock mass, which makes the blasting vibration velocity appear an amplification effect. At the same time, the damage evolution from the blast source to the surrounding rock mass corresponds to the change law of the peak vibration velocity, which can be used to determine if damage happens.

The dynamic response characteristics such as deformation capacity, acceleration, and load transfer of high-rise frame structure buildings under the condition of single column failure in different parts were studied. Firstly, according to the Code for Design of Concrete Structure (GB50010), a 4×6 span 8-story reinforced concrete frame structure model was established by using PKPM design software. Secondly, based on the component removal method, the finite element software SAP2000 was used to calculate the dynamic response characteristics of the frame structure with the failure of different single columns at the first floor, including the center column, long side middle column, short side middle column and corner column. The results show that the plastic angle is less than 6 for all the four column failure conditions, and the structure will not collapse. When the central column fails, the structural stability is the worst, and the probability of continuous collapse is the highest, followed by that of the short side and long side middle columns, and the corner column has the least probability. Under the condition of center column failure, the dynamic impact of the load on the residual structure is the most significant, with a maximum negative acceleration of about 3 g, which is twice as high as that of the short side middle column and the long side middle column. After the failure of the columns, the loads will be redistributed. The axial force will be borne by the adjacent columns, while the stress form of the upper beam will also change from bending to tension, resulting in a catenary effect. In the scenario of the central column failure, the axial force of the adjacent columns will increase by nearly 20%.

The dislocation and overbreak of tunnel inverted arch are serious when traditional blasting excavation technology is used. This is because traditional blasting technology does not adopt the smooth blasting method, and the angle of the perimeter holes is too large when drilled by manual rock drilling rigs. By therefore analyzing the traditional blasting excavation technique of invert, the cause of serious studiedthe smooth blasting technology for inverted arch is proposed based on the smooth blasting theory and a large quantity of engineering practice. Water decking charge structure is adopted in the perimeter holes, which can be adjusted according to the inverted arch shape. The spacing between the perimeter holes is 30~50 cm, and the thickness of the smooth blasting layer is greater than the perimeter hole spacing by 10~30 cm. Additionally, a drilling counterforce support is used to reduce the angle of the perimeter holes which can ensure each blast hole to be drilled to the design depth. After comparing the blasting effects of the proposed smooth blasting technology and traditional blasting technology for the inverted arch by field tests, the contour overbreak by the smooth blasting technology is far less than that of traditional blasting technology, and the cost of every 12 m tunnel excavation is reduced by 35.14%.