In order to analyze the general rules and causes of civil explosive accidents in China, statistical analysis was carried on the occurrence time, regional distribution, accident grade and other dimensions of nationwide civil explosive accidents from 2006 to 2023. Using analytic hierarchy process (AHP), a hierarchical structure model is constructed. It includes four first-level indicators (human, machine, environment and system) and 11 second-level indicators (safety awareness, technical training, supervision intensity, safety education, standardized operation, production equipment, production process, weather and climate, storage conditions, safety management system and emergency management system). Through analysis, the weight of each index is obtained, and then the importance of the influencing factors on explosion accidents is sorted. The results show that the number of explosion accidents has decreased year by year, and the safety situation is improved. The explosion accident time is concentrated in the second and third quarters of each year, and the space distribution is across all provinces with a staggered characteristic of “North-South and high-low”. Generally, the ordinary accidents and large accidents are the main accident levels. Based on the analytic hierarchy process (AHP), it is learned that human is the most important factor to cause the accidents in the first-level indexes. Meanwhile, the standardized operation, production process, supervision intensity and safety management system are the more important factors in the second-level indexes. Finally, according to the importance of the factors affecting the accidents, preventive measures such as strict standardization of operation, increasing safety input, strengthening supervision and improving safety management system are proposed.

Aiming at the problem of reasonable spacing-burden ratio in wide hole spacing blasting technology, laboratory blasting experiments of PMMA plates with the spacing-burden ratios of 1.7, 2.5, 3.5 and 4.5 were carried out based on related rock fragmentation mechanism at home and abroad. Meanwhile, a blasting calculation module was developed to study the crack propagation process and the response law of displacement based on the principle of near-field dynamics of conventional modes. The results show that the radial cracks present the character of branching to the corner of the free face and finally form the main cracks of a funnel shape, affected by the reflected tensile stress wave. Under the condition of fixed minimum resistance line, the stress reduction area gradually increases with the increase of the spacing-burden ratio, and the radial cutthrough cracks between the blastholes in the same row disappeared. An excessive spacing-burden ratio will further cause the disappearance of the cutthrough cracks between two rows of holes, and finally lead to the occurrence of individual hole blasting. The displacement results further confirm the above rule, and the rock ridge left by the front row of holes is just broken by the rear row of holes when the spacing-burden ratio is small. This breaking effect gradually decreases with the increase of the spacing-burden ratio. It is suggested that the spacing-burden ratio should be appropriately adjusted according to the mechanical properties of rock mass, geological conditions and blasting purposes to reduce explosive consumption and boulder yield in practical projects.

Structural plane is one of the key factors controlling the local stability of rock mass engineering. It is a prerequisite for rock mass stability analysis to find out the occurrence and combination of structural planes. Geological survey is often used at present. However, a high-cost supplementary survey is often needed when there are omissions due to the limitation of this survey means. Therefore, the surface vibration response law of the structural plane model was studied by laboratory tests. The study shows that the amplitude of the particle in front of the structural plane increases for the single structural plane model. For a block model cut by two structural planes, the amplitude-amplification effect exists only in front of the structural plane far from the power input side. Furthermore, the rock mass models with different structural plane dip angles were simulated respectively. The results show that, when the angle θ between the structural plane and the ground in the direction of the explosion source is less than 90°, the particle amplitude in the incident area of the vibration wave in front of the structural plane has an obvious amplification effect, and the particle amplitude behind the structural plane significantly attenuates. With the decrease of the angle θ between the structural plane and the boundary plane, the increase rate of the peak vibration velocity of the particle in front of the structural plane gradually increases, and the amplitude of the wave amplifies 2.8 times when θ=20°.

Aiming at the blasting demolition of the buildings embedded with a 43 m high steel structure boiler frame, the five boiler frames of No.2~No.6 boiler rooms were demolished by one-time directional blasting method and collapsed from north to south by span to east according to the order of No.2~No.6 boiler rooms. The reinforced concrete support columns were drilled and blasted, and the steel support columns were cut by a shaped energy cutter. Three cuts for the first-row of support columns of No.2 and No.3 boilers were set with a cut heigh of 6 m. Similarly, three 4m high cuts and two 3 m high cuts were set for the second-row and the third-row of support columns, respectively. The cut heights of the first-row and second-row of support columns of No.4~No.6 boilers were set as 6 m and 3.5 m, respectively. Additionally, the steel plates with a thickness less than 14 mm were cut by the SGPQ-15 (180 g/m) cutter, and the steel plates with a thickness of 16mm and 20 mm were cut by the SGPQ-19 (280 g/m) cutter. The total charge was 30.288 kg. During the explosion, the coal hopper room, boiler building roof and steel structure boiler frame overturned according to the designed direction. The frame of No.2 boiler sank at the moment of detonation, and the lower seat of No.5 column in the boiler room was placed after 0.25 seconds. Subsequently, the factory collapsed span by span from north to south and tilted towards the east with a detonation interval of 0.25 seconds. The collapse of the two stairwells were lagged significantly under the support of shear walls, and the stairwells toppled eastward under the impact of boiler overturning. The column between the upper and lower blasting cuts was compressed and collapsed during the tilting process of the column on the east side of the boiler room towards the east. The column was 16 m away from the chimney, and the upper part of the middle staircase, boiler, and shear wall were tilted forward. The main body was 14 m away from the chimney, and the closest distance of collapsed object to the chimney was 6 m. Both of the blasting flying stones and blasting vibration (0.28 cm/s) did not exceed the standard, and the blasting demolition did not cause any damage to surrounding buildings and facilities.

Shaped charge blasting technology plays an important role in goaf retaining roadway engineering, and the charge structure is always a hot and difficult issue in current discussions. At present, there is no clear indicator of the pre-splitting charge length of goaf-retaining roof. Taking the track groove of No. 2-11031 working face of the Mengjin Coal Mine as the research background, an isometric charge pre-splitting technology is proposed. Firstly, a three-dimensional directional shaped charge blasting model is established by LS-DYNA numerical simulation software to determine the optimal charge structure. By changing the axial cylinder length and taking the crack propagation length and stress decay rate as the analysis indexes, the numerical simulation shows that the radial slit distance is about 40 cm, and the axial slit distance is about 80 cm per meter when the axial uncoupling coefficient is between 1.25 and 1.7. Additionally, the slit distance is respectively increased by 25% and 12.5% compared with the axial uncoupling coefficient between 2 and 3. Furthermore, the energy utilization is the most reasonable as the stress attenuation rates are all less than 1 when the axial uncoupling coefficients are between 1.25 and 3. Finally, a roof directional blasting experiment with an axial uncoupling coefficient α=1.25~2 was carried out on the track groove of No. 2-11031 working face of the Mengjin Coal Mine. After the pre-split blasting, the middle line of the two holes was drilled and peeping. It is found that the cracks along the cutting seam direction between the two holes have been completely connected, the cracks are smooth, and the field application effect is good. Considering economy and safety, the uncoupling coefficient α=1.7 is the best. The results show that the isometric charging structure can replace the traditional three-stage charging structure.

Smooth blasting in tunnel construction needs decked charge in the peripheral holes. However, this charging method has certain limitations and risk of misfire due to the usage of detonating cord together with detonator. So, it is an urgent problem to improve the effect of smooth blasting and ensure tunnel excavation efficiency at the same time. Related research was conducted by field tests, and a new initiation technology of “Shaped device + digital electronic detonator” has been proposed, which was applied to a plateau tunnel. The experimental results show that, compared with the original technology, the powder factor by using the new technology has been reduced by 0.2 kg/m³, the half-hole rate is increased by 5%, and the average charge time is reduced from the original 1.3 h to 1.0 h. The tunnel excavation cycle footage is stabilized, and the cost of consumables is greatly reduced, and it is expected to be widely used in tunnel smooth blasting.

The distribution characteristics of blasting pile is an important index indicator to evaluate blasting effect. In view of the inadequacy of the current direct and indirect methods of measuring fragment size of the blast pile, a spatial distribution measurement method for adaptive stratification of the blast pile is proposed. It uses the GA-LSSVM model to predict the shape parameters α and β of the Weibull function and sets multiple prediction points to predict the three-dimensional blasting pile morphology. By converting and fusing the parameters of the Kuz-Ram fragment prediction model, a distance prediction model of blast pile stratification is established and applied to the Weibull-GA-LSSVM model to achieve an automatic stratification of the blast pile. Through field application, the stratification design is continuously optimized for the best stratification position to realize the adaptive stratification. The results show that: (1) the Weibull-GA-LSSVM model can accurately predict the morphology of the blast pile with a good stability that the average relative error of the prediction results of the maximum forward distance of the blast pile is only 5.6% and the relative error of the prediction results of the looseness coefficient is mostly around 9%. (2) The Kuz-Ram-based blast pile stratification model can reasonably output the layer distance and number before blast, which ensures the shoveling efficiency after blast. (3) The optimal layer distance formula is derived to achieve the adaptive stratification of the blast pile, and the measurement accuracy of the fragment size distribution of the blast pile is significantly improved, which is closer to the overall fragment size distribution.

An equal proportion separated common node model was established by ANSYS/LS-DYNA finite element software to simulate the collapse process of a frame structure with a small height-width ratio demolished by blasting, and the stress characteristics of reinforced concrete columns of the structure were analyzed. It is found that the actual engineering and simulation results are highly consistent in terms of collapse time, collapse process and blast muck pile range, which shows that the numerical simulation is reliable. Additionally, during the collapse process, the plastic hinge was generated at the beam-column joints after each row of columns reached the section resistance moment, and the upper structure rotated with the plastic hinge as the fixed axis. There was a backward reaction force on the rear column, which resulted in an obvious recoiling in the forward leaning process. In the early stage of collapse, the stress of the reinforcing bar and the concrete element is stressed together. The stress of the reinforcing bar element with its co-node suddenly changed after the failure of the concrete element, and then it continuously changed in the state of tension and compression until the collapse ended. The reinforced bar at the blasting cut has certain hindrances to the free fall of the upper structure.

Aluminum powder is the most used metal fuel in explosives industry. The nano aluminum powder has a much higher specific surface area, reaction reactivity and completeness compared with the micron aluminum powder. Therefore, the application of nano aluminum powder in explosives will undoubtedly improve the explosive power and the ammunition damage efficiency. This article has systematically reviewed the effects of nano aluminum powder on the detonation performance, safety performance, process performance and other explosive properties. As for the detonation performance, the nano aluminum powder can improve almost all detonation parameters of the mixed explosive, including the detonation velocity and heat, the peak value of shock wave overpressure of air explosion, the total energy of underwater explosion, the peak value of explosion pressure and the rise rate of explosion pressure of the fuel-air explosives, the metal acceleration ability, arson ability, work ability, and brisance, et al. However, some incorrect conclusions are often drawn by some researchers due to the low effective aluminum contents of the nano aluminum powder. In terms of safety performance, the introduction of nano aluminum powder increases the impact sensitivity, friction sensitivity, shock wave sensitivity and thermal sensitivity of mixed explosives, which significantly reduces the ignition energy of explosives and promotes the thermal decomposition of common explosives (such as TNT, RDX, HMX, CL-20, NG, etc.). Therefore, the introduction of nano explosives has a negative influence on the safety performance of mixed explosives. In terms of process performance, the nano aluminum powder increases the viscosity of the cast explosive system. However, it reduces the density of the explosive column in the pressed explosive system. Therefore, the introduction of nano-aluminum explosive deteriorates the process performance of the mixed explosive. It is pointed out that it is easy to oxidize in various stages from preparation to storage due to the large specific surface area and high reaction activity of nano aluminum powder, which results in a sharp decrease in the effective aluminum content of nano aluminum powder. This is an important reason why some researchers get wrong conclusions. Therefore, it is necessary to study the preparation methods and storage conditions to make full use of nano aluminum powder in explosives.

The blockage of a fine ore bin is a common problem during the process of the beneficiation and smelting of non-ferrous metal mine due to its inherent structure, the properties of fine ore and environmental factors. The treatment methods such as air gun and manual knocking are inefficient and labor-intensive, which cannot meet the production requirements. It is a feasible way to dredge the blockage of the fine ore bin by controlled blasting. The key to handling the blockage by blasting is to determine the explosive charge amount under the condition of ensuring safety. According to the blockage position and degree, two kinds of charge calculation formulas were used by analyzing the reason for the fine ore bin blockage, the characteristics of the blockage body and the principle of blasting dredging. One method is refer to the empirical formula of condensate disassembly blasting. The charge amount for viscous plugging is designed and calculated according to the slagging thickness. The calculations indicate that the charge for the upper part with a larger diameter is 0.59 kg, while the charge for the lower conical feeding port with a smaller diameter is 0.07 kg. The other method is according to the calculation principle of volume charge and the characteristics of the clogging body of the fine ore bin. The calculations indicate that the charge for the upper part with a larger diameter is 0.49~0.98 kg, while the charge for the lower part with a smaller diameter is 0.15~0.30 kg. The safety charge amount is determined through calculating the safety pressure by the Faupel correction formula and shock wave calculation. As a result, the charge amount for the upper part and the lower part are determined as 0.6 kg and 0.15 kg, respectively. During the implementation process, 15 blocked fine ore bins were treated by charge amounts not exceeding 0.6 kg and 0.15 kg, all of which were safely dredged as expected. The practice shows that the calculated charge amount is reasonable, and the safety measures are effective.