A large-area concrete site was prepared to eliminate the boundary effects to investigate the propagation law of detonation-induced cracks in differential blasting under varying hole spacing. Multiple sets of linear three-hole and cross-five-hole model tests were conducted using electronic detonators and detonating cords as the blasting sources. The propagation length, direction, and crack arrest position of detonation cracks were recorded under different blasting parameters. The key factors affecting crack propagation were identified by combining the experimental results with the theory of sequential controlled blasting. The results indicate that in the three-hole model, a through-crack forms between the blast holes when the middle hole detonates first, followed by the two side holes. However, as the hole distance increases, the crack becomes increasingly irregular. When the distance reaches 25 times the hole diameter, the crack fails to penetrate and no longer propagates along the direction of the blast holes. In the cross five-hole model, a through-crack can only form when the spacing is within 20 times the hole diameter. The crack generated by the first blast tends to propagate towards the nearest subsequent hole. Still, it does not follow a straight path, exhibiting deflection due to the influence of the additional holes. Therefore, to achieve straight cracks along the contour surface in practical engineering, it is crucial to adjust the timing and control blasting parameters based on specific hydrogeological conditions to fully utilize the void effect and the detonation timing difference.

The original stope benches of Dahuangshan Open-pit Mine were in disarray, with pumice between benchs and steep slope conditions. Following blasting operations, a crushing system was introduced to improve rock fragmentation efficiency, significantly increasing potential safety risks near high and steep slopes. This study researched safe blasting techniques and protective measures for slopes in open-pit mines to ensure slope safety during blasting construction. Active protection methods were proposed, including limiting instantaneous charge to 200 kg, aligning the blasting direction parallel to the slope, and preserving approximately 5 m of rock wall along the slope edge. Protective infrastructure was enhanced by installing two protective nets on a cleaning platform mid-slope, excavating a 7 m-deep and 20 m-wide stone protection ditch at the foot of the slope, building a 2 m-high stone protection wall using crushed stones outside of the ditch, and erecting a 2 m-high isolation net outside the protection wall. These safety measures were complemented by auxiliary monitoring methods to enhance the safety of blasting operations and protect the crushing system. Field inspections confirmed that the construction methods effectively ensured the stability of the high-steep slopes and minimized risks during blasting.

A novel energy dissipation blasting technique based on water coupling is proposed to explore new methods for rapid excavation of spillway protection layers in hydropower stations under relatively intact hard rock conditions. This method specifically addresses the excavation requirements of the Nam Kong 1 Hydropower Station spillway in Laos. By increasing borehole pressure, the technique generates stronger stress, which is advantageous for excavating hard rock formations. Simulation analysis using LS-DYNA software demonstrates that coupling water-charged explosives with a blocked borehole bottom amplifies the peak load on the borehole walls and extends the explosive load duration, thereby improving the fragmentation of harder rock at the borehole bottom. Results indicate that the combination of bottom-hole blockage and water-coupled charges increases lateral damage depth and prolongs load application time, thus achieving more effective excavation and formation in relatively intact hard rock. Comprehensive evaluations based on numerical simulations and field test parameters confirm that this approach significantly improves the quality of excavation and formation of the first-stage stilling basin floor in practical engineering applications.

Safety management plays a vital role in blasting operations, and blasting safety is closely related to the processes of drilling, blasting, loading, transportation, and dumping, with significant interactions among these procedures. However, due to the diverse sources and complex structure of current blasting safety data, the lack of systematic integration poses challenges for on-site personnel to accurately acquire critical safety knowledge under complex working conditions. To address this issue, this study applies a BERT-BiLSTM-CRF-based method for entity recognition in the field of blasting safety management. The BERT pre-trained model is first used to obtain dynamic word embeddings, followed by optimal label sequence tagging using the BiLSTM-CRF model. A knowledge graph covering seven entity types and nine relationship types is constructed and stored using the open-source Neo4j graph database system. Experimental results show that the F₁-score for all entity types exceeds 60%, demonstrating that the proposed model significantly improves entity recognition accuracy compared to traditional models. Based on this, a knowledge graph-based Q&A system for blasting process safety management in open-pit coal mines is developed, enabling rapid querying of domain knowledge and efficient matching of various blasting processes with safety standards. With the support of this Q&A system, on-site engineers can make timely and informed decisions in complex blasting safety management scenarios.

Reinforced concrete structures are usually subjected to explosion impact load, resulting in severe damage. Different protective materials are typically laid on reinforced concrete slabs to improve the explosion resistance. The experimental study on the explosion resistance of reinforced concrete slabs with different protective materials was conducted using the drop hammer test, and an accelerometer tested the impact of reinforced concrete. An embedded piezoelectric intelligent aggregate is used to monitor the internal damage signal of a reinforced concrete slab under the drop hammer impact load. The test results show that both carbon fiber reinforced matrix composites (CFRP) and polyurea can effectively protect the specimens in the single-layer reinforced structure, with an average decrease of 78.20% and 79.05% relative to reinforced concrete acceleration and 40.98% and 65.79% peak impact stress, respectively. Additionally, the average acceleration reduction of polyurea-concrete-CFRP (IPC), polyurea-CFRP-concrete (ICP), and CFRP-concrete-polyurea (CIP) compared with reinforced concrete slabs are 70.29%, 77.46% and 79.85% in the composite protective structure, respectively. The average peak impact stress reduction is 32.73%, 56.32%, and 51.07%, respectively, which can effectively protect the specimens and improve the impact resistance of concrete slabs. It can provide a reference for related engineering applications.

Pre-splitting blasting has been widely employed in river channel slope excavation to effectively mitigate damage to the retained rock mass, reduce blast-induced vibrations, and optimize blasting parameters for water-saturated slopes. Investigation of reasonable parameters for pre-splitting blasting in such conditions is important for river channel excavation projects. Based on geometric, physical, and dynamic similarity principles, an experimental model for pre-splitting blasting water-saturated slopes was designed, utilizing concrete as a substitute for red sandstone and detonators instead of emulsified explosives. The quality of pre-split crack formation, slope face shaping, and retained rock mass damage were evaluated under various conditions. The results showed that the pre-split crack formation quality and slope shaping quality significantly improved. The damage to the retained rock mass was reduced by 24.86% when the hole diameter increased from 0.8 cm to 1.2 cm. Field test results indicated that the optimal blasting effect can be achieved with a pre-split hole diameter of 115 mm and a hole spacing of 80 cm in a practical application of pre-splitting blasting for water-saturated slopes when the geological conditions involve medium-hard rocks.

Underwater blasting vibration poses significant challenges in mining engineering applications, particularly channel dredging, seaport, and bridge construction. This study investigates the vibration attenuation mechanism and propagation characteristics through damping borehole configurations. The attenuation law of underwater blasting damping holes was studied, and a comprehensive experimental program to analyze the blasting vibration signals and piezoelectric signals was conducted by comparing three scenarios: conventional blasting without damping measures, water-coupled damping holes, and air-coupled damping holes. The optimized borehole parameters included a 2 cm diameter, 5 cm spacing, 4 cm row spacing, and 17 cm depth, positioned 20 cm from the explosive source. Experimental results demonstrated that using underwater blasting damping holes can effectively reduce the peak vibration velocity of blasting. The average damping rate of water-coupled damping holes and air-coupled damping holes is 17.5% and 27.2%, respectively. Time domain analysis revealed a consistent correlation between piezoelectric signals and the peak vibration velocity. The damping mechanism primarily affected vertical vibration components, with effectiveness positively correlated with charge weight. Field validation tests confirmed an 18.1% vibration reduction, establishing the practical efficacy of the proposed damping borehole array.

As a main mean of open-pit mining, bench blasting is still an irreplaceable production method at present and even in the future. By deeply analyzing the measured data of bench blasting and using 3DEC software to simulate the bench blasting process, the internal rock mass movement trajectory and muckpile distribution during the bench blasting process were revealed. The research results show that the monitoring points generally rose along the vertical direction first and then fell during the blasting process. Among them, the movement of the monitoring points on the upper part of the monitoring hole were more obvious in the vertical direction, rising to a certain height and then quickly moving vertically downward. While the monitoring points on the lower part of the monitoring hole mainly moved forward in the horizontal direction, and the vertical direction movement is relatively weak. At the same time, in order to study the spatial distribution of the muckpile, the bench in the research area were divided into six parts, as Ⅰ~Ⅵ. Besides, the main part (0~40 m) of the muckpile was divided into four regions, as A, B, C and D. According to the simulation results, it can be found that the Ⅴ rock mass accounts for the most in region A (muckpile 0~10 m), which is as high as 41.7%. The Ⅰ~Ⅴ rock mass distribution is relatively even in region B (muckpile 11 m~20 m). The Ⅰ~Ⅲ rock mass accounts for 43.1%, 37.5% and 19.3%, respectively, and the Ⅳ rock mass accounts for a very small part in region C (muckpile 21~30 m). It is basically composed of the Ⅰ rock mass in region D (muckpile 31~40 m) at the forefront of the blast muckpile, which accounts for 95%.

Based on the blasting demolition of a 7-storey frame-shear wall structure in Wuhan, this study investigates the impact of different incision patterns on the collapse process. A refined finite element numerical model was established using ABAQUS, with steel and concrete supporting columns modeled separately and the upper collapse body modeled as a whole. This approach enables accurate simulation of the mechanical behavior of supporting columns while improving computational efficiency. A triangular incision form model was also developed and compared against the trapezoidal incision form used in the project. The stress distribution, recoil distance, and collapse motion characteristics of supporting columns under the two different incision forms were analyzed to explore their effects on the collapse process. Results indicate a high consistency between the numerical simulation and the actual collapse regarding timing, motion characteristics, and overall process, validating the modeling approach. Compared to the trapezoidal incision form, the triangular incision form features a lower center of gravity, causing the structure to tilt quickly around the incision vertex post-detonation. This leads to rapid failure of the rear-row support columns under large eccentric pressure. Consequently, the collapsed body makes ground contact faster, at a higher velocity and disintegrates more thoroughly. Additionally, the triangular incision generates greater horizontal kinetic energy, resulting in a larger recoil distance. This analysis highlights the significance of incision form selection in optimizing blasting demolition outcomes.

The occurrence of oversized fragments during blasting operations significantly increases the cost of blasting, crushing, and hauling expenses. This study addressed the slab' phenomenon observed in the blasting of intact hard rock at the Pingtanyuan Pumped Storage Power Station, where the oversized fragments of the surface blasting area was up to 6 m×5 m×2.5 m. Through comprehensive mechanism analysis, the investigation indicated that the quality of the stemming was the key reason for forming large fragments at the upper part. Meanwhile, the mechanism of its influence lies in the over-long stemming length of the original blasting scheme, which resulted in a low charge center, leading to insufficient energy distribution at the top of the blast hole. Furthermore, an oversized blasting fragments control measurement based on stemming quality optimization was proposed. The stemming length was optimized from 3~4 m to 2.1~2.4 m using a time-sharing piecewise calculation method and the optimization principle, which allowed the part of the stemming structure to rush out of the blast hole. Besides, the decontaminated rock chips were used as stemming material. The results show that the optimized scheme prevented the occurrence of the slab phenomenon, significantly reduced boulder rates, and saved rock breakage costs.