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    Information & Control
    Defect Detection on PCB Based on Improved YOLOv8
    Zhen-zhen LYU, Li-jin FANG, Qian-kun ZHAO, Ying-cai WAN
    2025, 46 (10):  1-9.  DOI: 10.12068/j.issn.1005-3026.2025.20240038
    Abstract ( 381 )   HTML ( 7)   PDF (10197KB) ( 35 )  

    Due to the high integration, complex circuits, and increasing parameters of printed circuit boards (PCBs), defects in PCBs directly affect production efficiency, making computer vision-based defect detection crucial for PCB manufacturing. A self-attention-based PCB defect detection algorithm was proposed based on the YOLO object detection algorithm. First, a polarized self-attention (PSA) mechanism was introduced in the feature extraction stage to separately extract spatial and semantic features of PCBs, which were combined with input raw features to enhance the network’s feature representation capability. Then, a small-object detection head was added in the decoding stage, which fully utilized low-resolution features from the YOLO network Backbone module to enable the network to focus on local details of PCBs and improve defect positioning accuracy. Experiments show that the proposed method achieves 95.5% accuracy on the PCB dataset, 4% higher than the original YOLOv8 method, with the mAP0.5∶0.95 metric increased by 2.8%.

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    Comprehensive Identification of Influential Spreaders in Temporal Networks Considering Multiple Features
    Hai ZHAO, Shu-kun YANG, Jiu-nan MIAO, Xue-long YU
    2025, 46 (10):  10-17.  DOI: 10.12068/j.issn.1005-3026.2025.20240057
    Abstract ( 193 )   HTML ( 2)   PDF (1187KB) ( 12 )  

    Accurately identifying influential spreaders in temporal networks is crucial for product promotion, rumor suppression, and other aspects. Existing methods mostly rely on a single feature (the number of neighbors, node location, or propagation ability) and ignore interactions between features, resulting in low accuracy. Therefore, a temporal gravity(TG)model and an information entropy-based identification method(TGBISR)were proposed to improve identification accuracy by fusing multiple features. First, the TG model was used to analyze the degree centrality, closeness centrality, and betweenness centrality of the user, portraying their local, positional, and global features, respectively. Then, the information content of each feature was measured through information entropy, and different weights were assigned to them to comprehensively compute the user’s influence. To verify the result, the susceptible-infected-recovered (SIR) model was used to simulate information dissemination on four real datasets to obtain the real influence of users. The correlation between the TGBISR calculation results and the real values was then compared using Kendall’s correlation coefficient and regression analysis. The experimental results show that the TGBISR method’s calculated results exhibit a higher statistical correlation with the true influence of the SIR model when identifying influential spreaders, and its accuracy significantly and consistently outperforms that of the other five benchmark algorithms.

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    LIDD-Net: Lightweight Industrial Product Defect Detection Method Based on Deep Learning
    Xiao-peng SHA, De-han XIE, Zhou-peng GUO, Kai SUN
    2025, 46 (10):  18-26.  DOI: 10.12068/j.issn.1005-3026.2025.20240058
    Abstract ( 360 )   HTML ( 1)   PDF (2555KB) ( 12 )  

    In industrial products, various types of defects often exhibit high inter-class similarity, large scale variations, and complex backgrounds. To address these challenges, a lightweight industrial defect detection network (LIDD-Net) was proposed. To handle highly similar defect types, in LIDD-Net, a channel interaction separation backbone network was introduced, which enhanced feature extraction while reducing the computational cost of the model. To address multi-scale defect variations, a lightweight feature fusion network was developed, namely RepGhostPAN, to efficiently integrate multi-scale features in the image and accelerate inference. For complex detection backgrounds, a lightweight auxiliary training module was proposed, leveraging an auxiliary training head and a dynamic soft label assignment strategy to better distinguish target defects from complex backgrounds. Experiments on steel, aluminum, and tire defect datasets demonstrate that LIDD-Net achieves mAP@0.5 scores of 98.3%, 98.1%, and 96.1%, respectively, with only 0.62×106 parameters, meeting practical industrial requirements.

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    Identification of Wiener Systems Based on LVW-LM-QN Algorithm
    Miao YU, Wan-li WANG, Yong-tao WEI
    2025, 46 (10):  27-35.  DOI: 10.12068/j.issn.1005-3026.2025.20240061
    Abstract ( 324 )   HTML ( 3)   PDF (1354KB) ( 12 )  

    Wiener systems, consisting of a linear dynamic subsystem and a static nonlinear subsystem in series, find extensive application in process industries such as petroleum and chemical engineering. Obtaining the model of Wiener systems holds significant importance. A nonlinear system identification method based on the linear variable weight–Levenberg Marquardt–quasi Newton (LVW-LM-QN) algorithm for Wiener systems was proposed. The Wiener system was divided into two subsystems for separate processing. For the linear dynamic part, the subspace identification method with the canonical variate analysis (CVA) algorithm was used for parameter estimation, whereas for the subsequent nonlinear static part, the LVW-LM-QN algorithm was employed for identification. Finally, the method was evaluated through numerical examples and an application case of liquid level control in a two-tank system, and the effectiveness and accuracy of the proposed method were verified by the simulation results.

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    Shi-Tomasi Corner Detection Method Based on Adaptive Threshold Canny Edge Detection
    Yao ZHANG, Yu SUN, Qing-he LIN, Huai WANG
    2025, 46 (10):  36-43.  DOI: 10.12068/j.issn.1005-3026.2025.20240067
    Abstract ( 281 )   HTML ( 1)   PDF (1621KB) ( 5 )  

    The traditional Shi-Tomasi corner detection algorithm has been widely applied in many fields of computer vision. However, this algorithm has low efficiency and accuracy, poor noise resistance, and is prone to producing false corners. A method that combined adaptive threshold Canny edge detection and improved Shi-Tomasi corner detection was proposed. Firstly, improved Canny edge detection was used to extract image edges and screen candidate corner points, while a one-dimensional information entropy adaptive threshold was used to adapt to different image environments, thereby improving the efficiency and robustness of detection. Secondly, using circular templates for non-maximum suppression reduced the number of false corner points and enhanced the algorithm’s ability to recognize true corners. Finally, the improved Shi-Tomasi algorithm was applied to the extracted edge images for corner extraction, thereby achieving accurate image localization. The experimental results show that compared with the traditional algorithm, the proposed method has significant improvements in runtime and accuracy, and it has significant advantages in rotation invariance and noise resistance.

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    3D Gesture Estimation Algorithm Based on Geometric Attention Mechanism
    Hui ZOU, Li-huang SHE, Ye-han CHEN, Yi YUE
    2025, 46 (10):  44-50.  DOI: 10.12068/j.issn.1005-3026.2025.20240079
    Abstract ( 355 )   HTML ( 2)   PDF (2154KB) ( 9 )  

    A gesture recognition network based on the coding and decoding infrastructure of Transformer was designed, and an optimized offset attention mechanism was introduced to extract hand features based on the self-attention mechanism. At the same time, in order to extract the local features of the hand structure better, a neighborhood aggregation strategy was designed. The three-dimensional (3D) complexity of the hand structure itself led to different levels of smoothness in different regions. When estimating gestures, ignoring this feature usually leads to the loss of local key information of the hand structure. In order to solve this problem, geometric decomposition of the hand structure was carried out, and sharp and flexible components were used to represent the sharp and flat regions of the hand structure, respectively. Different attention was paid to the characteristics of these two components through the attention mechanism. Experiments on MSRA, ICVL, and NYU datasets demonstrate that the accuracy of this algorithm is comparable to that of SOTA.

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    Materials & Metallurgy
    Intelligent Prediction for Endpoint Mass Fraction of Carbon in Molten Steel of RH
    Deng-hui LI, Yan ZHAO, Hong LEI, Jia FAN
    2025, 46 (10):  51-58.  DOI: 10.12068/j.issn.1005-3026.2025.20240051
    Abstract ( 349 )   HTML ( 2)   PDF (1269KB) ( 12 )  

    Accurate prediction of the endpoint mass fraction of carbon in the molten steel of RH (Ruhrstahl Heraeus) can effectively improve the quality of continuously cast products. In order to realize this goal, data mining was firstly applied to preprocess the RH industrial data. Then, grey correlation analysis, Spearman correlation coefficient, and random forest out-of-bag error scoring were used to select the features that had a strong correlation with the endpoint mass fraction of carbon in the molten steel. Next, the principal component analysis method was applied to reduce the dimensions. Finally, the XGBoost model, the XGBoost model optimized by the particle swarm optimization algorithm, and the XGBoost model optimized by the whale optimization algorithm were applied to predict the endpoint mass fraction of carbon in the molten steel. The results show that grey correlation analysis is better than Spearman rank correlation coefficient and random forest in analyzing the selected features. After the optimization of the particle swarm optimization algorithm and whale optimization algorithm, the XGBoost model has a greater prediction hit rate. The XGBoost model optimized by the whale optimization algorithm is better than that by the particle swarm optimization algorithm. In the case of the XGBoost model optimized by the whale optimization algorithm, the hit rate reaches 91.26% and 98.97% if the error range is within ±5×10-6, and ±7×10-6.

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    Ordering Transition of L10-FeNi Promoted by Doping Bi/Pb/Au/Cu with First Principles
    Qun-shou WANG, Jia-yu TANG, shuang YAO, Wen-li PEI
    2025, 46 (10):  59-65.  DOI: 10.12068/j.issn.1005-3026.2025.20240052
    Abstract ( 258 )   HTML ( 4)   PDF (2484KB) ( 9 )  

    The FeNi material with L10 ordered structure has excellent magnetic properties and broad application prospects. However, the formation temperature of the L10 structure in FeNi is low, and the atomic ordering diffusion is slow at this temperature. Therefore, it is difficult to directly synthesize L10-FeNi in the experiment. The effects of doping with Bi, Pb, Au, and Cu elements on the ordering diffusion and magnetic properties of FeNi were investigated by using the first principles. The results show that doping with a third element can effectively improve the formation kinetics of FeNi, thereby promoting the ordering transition of FeNi. Among them, Au and Cu elements are easier to substitute for the matrix atoms and are doped into the lattice, which is more conducive to the stability of the structure. Bi, Pb, Au, and Cu are more likely to occupy the Fe site. The doping of elements can effectively reduce the vacancy formation energy of FeNi, which reduces the diffusion activation energy and promotes the diffusion and transfer of Fe and Ni atoms. Therefore, the disorder-order transition barrier of FeNi can be lowered to effectively improve the ordering transition of FeNi. The doping of third elements at the Ni site has little effect on the electronic structure and magnetic properties of FeNi.

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    Mn-Doped CaO Catalytic-Adsorption Synergistic Mechanism for Denitration and Carbon Reduction Based on DFT
    Rui GUO, Hua-qing XIE, Zhen-yu YU, Zheng-ri SHAO
    2025, 46 (10):  66-73.  DOI: 10.12068/j.issn.1005-3026.2025.20240053
    Abstract ( 309 )   HTML ( 3)   PDF (6283KB) ( 15 )  

    A dual-functional catalyst with CaO as the substrate and Mn as the dopant metal was constructed using density functional theory (DFT). The adsorption behaviors of NO, CO and carbon reduction reactant (CO2) were studied, alongside the reaction mechanisms for denitration and carbon reduction. Results show that CO and NO adsorb on the CaO surface through weak and strong chemical adsorption, respectively, with Mn doping enhancing adsorption for both. The Mn-doped CaO catalysts also exhibit excellent CO2 adsorption properties, making them effective decarbonization carriers. The rate-determining step for the CO-SCR reaction is the dissociation of NO, with Mn doping lowering its energy barrier by approximately 0.27 eV. As temperature increases, the free energy barrier of the rate-determining step reaction over the Mn-CaO catalyst gradually rises, while the absolute value of the free energy change for the CO2 adsorption reaction gradually decreases, demonstrating the catalyst's superior low temperature denitration and decarbonization performance. This study offers new insights for developing dual-functional catalysts for simultaneous denitration and carbon reduction.

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    Influence of Inert Gases on Flammability Limit of C2H6 and Their Formation Causes
    Chang YUAN, Xian-zhong HU, Juan ZHANG
    2025, 46 (10):  74-80.  DOI: 10.12068/j.issn.1005-3026.2025.20240054
    Abstract ( 172 )   HTML ( 1)   PDF (2556KB) ( 6 )  

    The flammability limit of ethane in O2/inert gases (N2, Ar, CO2) atmosphere was experimentally determined in a 5 L constant volume combustion bomb. Among the three inert gases, CO2 is of the greatest influence on the flammability limit. For the lower flammability limit, Ar and N2 decreased it slightly, while CO2 increased it from 3.40% to 4.65%. The upper flammability limit changed more significantly; as the inert gas concentration increased from 10% to 80%, CO2 reduced it from 51.5% to 8.0%, a reduction of 43.5%, while Ar and N2 reduced it by 39.0% and 40.0%. The dilution, chemical, thermodynamic, and radiation effects of inert gases were separated with the limiting laminar burning velocity method. The results show that N2 only produces the effects of dilution and radiation, while Ar and CO2 produce four effects. At the lower flammability limit, the dilution effect of N2 is the strongest, accounting for 99.2% of the total effect, and the thermodynamic effect of Ar and CO2 is the largest, accounting for 64.4% and 51.4% of the total effect, respectively. For the upper flammability limit, the dilution effect is always of the greatest influence.

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    Combined Supply System with Deep Coupling of C-GSHP and COG-CCHP
    Ming-jie FENG, Deng-liang WANG, Yu-qian XIA, Sheng-hui LIU
    2025, 46 (10):  81-88.  DOI: 10.12068/j.issn.1005-3026.2025.20240056
    Abstract ( 240 )   HTML ( 1)   PDF (1864KB) ( 7 )  

    A novel multi-energy combined supply system was proposed by deep coupling a cascade ground source heat pump (C-GSHP) system and a coke oven gas-based combined cooling, heating and power (COG-CCHP), so as to maximize the utilization of waste heat from the CCHP subsystem, enhance energy utilization efficiency, and adjust to China’s current energy landscape. Based on the Aspen Plus platform, the simulation operation, thermodynamic analysis, and sensitivity analysis of the system’s important parameters were completed. The results indicate that the system’s primary energy utilization efficiency and exergy efficiency are 95.12% and 35.12%, respectively, greater than the traditional system’s 83.80% and 31.80%. The exergy efficiency of compressors and circulating pumps is relatively high, while that of heat exchangers is relatively low. The exergy loss mainly occurs in the combustion chamber and the steam-water heat exchanger, accounting for 48.7% and 29.9% of the total exergy loss of the entire system, respectively. When other parameter values are fixed, the intermediate temperature of the heating circulating water and the outlet pressure of the upper-level circulating compressor are positively correlated with the power consumption of the cascade heat pump circulation subsystem, while the evaporator pressure is approximately negatively correlated with the power consumption of the cascade heat pump circulation subsystem.

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    Phase Equilibrium Relationships of CaO-Al2O3-Ce2O3-CaF2 Slag System at 1 400 ℃ in Argon
    Jiang-sheng YE, Cheng-jun LIU, Zhi-gang LIANG, Ye-guang WANG
    2025, 46 (10):  89-95.  DOI: 10.12068/j.issn.1005-3026.2025.20240059
    Abstract ( 265 )   HTML ( 1)   PDF (6405KB) ( 11 )  

    In order to fill the gap in thermodynamic research and thermodynamic data of metallurgical slag system of rare earth steel, the phase equilibrium relationships and liquid phase distribution of CaO-Al2O3-Ce2O3-CaF2 slag system at 1 400 ℃ in argon were determined by the high-temperature thermodynamic equilibrium experiment and scanning electron microscope-energy dispersive spectrometer (SEM-EDS), and the isothermal phase diagram was plotted. Eight equilibrium coexistence regions in the CaO-Al2O3-Ce2O3-CaF2 slag system were determined at 1 400 ℃ in argon, including a single liquid phase region, four two-phase equilibrium regions (L+C11A7F, L+C2A3Ce, L+C2ACe, and L+CA2), and three three-phase equilibrium regions (L+C+C2ACe, L+C2ACe+C11A7F, L+CA2+C2A3Ce). The liquid phase region of the CaO-Al2O3-Ce2O3-CaF2 slag system at 1 400 ℃ in argon was determined by the liquid phase boundary in the two-phase equilibrium regions.

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    Numerical Simulation on Deformation Behavior of High-Carbon Steel Billet During Mechanical Reduction Process
    Yu-bo GAO, Yan-ping BAO, Min WANG, Ying WANG
    2025, 46 (10):  96-103.  DOI: 10.12068/j.issn.1005-3026.2025.20249012
    Abstract ( 278 )   HTML ( 2)   PDF (1607KB) ( 9 )  

    The deformation behavior of the high-carbon steel billet in the continuous casting mechanical reduction process was analyzed from aspects such as appearance deformation, two-phase region deformation, and strain by establishing a 3D thermal-mechanical coupling numerical model. The research results show that the deformation behavior of the high-carbon steel billet during the mechanical reduction process is closely related to the amount and the position of mechanical reduction applied. A larger reduction amount indicates a larger overall appearance deformation of the billet and a more reduced area of the two-phase region caused by the mechanical reduction; the strain generated inside the billet also increases, while the reduction efficiency decreases with the increase in the reduction amount. As the reduction position moves forward, the deformation trend of the billet expanding in the width direction on both sides has intensified, and the reduction efficiency increases. Furthermore, as the central solidification rate corresponding to the reduction position decreases, the intensity and area of the lateral tensile strain in the spread direction acting on the central region of the billet show an increasing trend.

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    Theoretical and Experimental Research on Dimensional Shrinkage of MFFF 17-4PH Products
    Shi-jie JIANG, Fei WANG, Shu-guang LI, Zi-zhao XU
    2025, 46 (10):  104-112.  DOI: 10.12068/j.issn.1005-3026.2025.20240013
    Abstract ( 182 )   HTML ( 1)   PDF (2422KB) ( 6 )  

    The dimensional shrinkage of the green sample treated by metal fused filament fabrication (MFFF) occurs during debinding/sintering process, affecting the forming accuracy and practical application. In order to clarify the shrinkage mechanism and put forward effective solutions, a theoretical model of the dimensional shrinkage rate of sintered samples was first established, and the dimensional changing process was theoretically analyzed. Then, a sintered sample of 17-4PH stainless steel was formed, and the microstructure of its cross-section was determined using scanning electron microscope (SEM). Through the comparison between the theoretical and experimental results, the correctness of the proposed model was verified. Finally, the sensitivity of the model was analyzed, and the influence of the sintering temperature rise rate, maximum temperature holding time, and apparent density of the green sample on the dimensional shrinkage rate of MFFF samples was discussed. The results show that the dimensional shrinkage rate of the samples is anisotropic (the one in the vertical direction is slightly larger than that in the horizontal direction). The apparent density of the green sample has the most significant effect on the dimensional shrinkage rate of the sintered samples, followed by the sintering temperature rise rate and maximum temperature holding time.

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    Resources & Civil Engineering
    Influence of Displacement Ventilation on Local Exhaust Ventilation and Analysis of Ventilation Efficiency
    Xiu-li LIN, Yu-hong ZHOU, Jing-xian LIU
    2025, 46 (10):  113-122.  DOI: 10.12068/j.issn.1005-3026.2025.20240066
    Abstract ( 215 )   HTML ( 1)   PDF (4735KB) ( 14 )  

    The method of coupling displacement ventilation and mobile local exhaust ventilation can improve the control effect of welding fume generated at non-fixed points in a large-space workshop, but the influence of ventilation parameters on the control effect still needs to be clarified. The effects of air supply velocity and angle during displacement ventilation on the fume capture efficiency of the local exhaust hood were explored when parameters such as distance between local exhaust hood opening and welding point, air velocity at hood opening, and relative position between welding point and air supply outlet during displacement ventilation changed, and the coupled ventilation efficiency was analyzed. The results show that when the air supply angle is 0° (horizontal), a higher air supply velocity during displacement ventilation has a greater impact on the local exhaust ventilation. A higher air supply velocity at the local exhaust hood opening and a closer distance from the hood opening to the welding point mean that its fume capture efficiency is less affected by displacement ventilation. A closer distance from the welding point to the air supply outlet during displacement ventilation indicates a greater impact of displacement ventilation on local exhaust ventilation. Increasing the air supply angle can weaken the impact. The efficiency of coupled ventilation is higher than that of single displacement ventilation, which can be stabilized to 80% within 15 min. Research results can provide a basis for the design and management of the coupled ventilation system.

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    Caving Mechanism and Treatment Method of Overlying Rock in Adjacent Goaf Disturbed by Ore Pillar
    Jian-li CAO, Feng-yu REN, Dong-jie ZHANG
    2025, 46 (10):  123-131.  DOI: 10.12068/j.issn.1005-3026.2025.20240069
    Abstract ( 143 )   HTML ( 1)   PDF (12307KB) ( 11 )  

    The ore pillar between adjacent goaf usually accumulates a large amount of energy, and the ore pillar instability will lead to large-scale caving hazard accidents. Therefore, a caving-induced mechanical model of goaf was constructed. The caving characteristics and mechanism of the overlying rock in the adjacent goaf were studied through physical experiments and numerical simulation, and a new method of caving induced by ore pillar treatment of the adjacent goaf was proposed. The results show that the existence of the ore pillar can carry a certain amount of energy accumulation, so that the overlying rock above the ore pillar is deformed and destroyed to a certain extent. After the ore pillar is removed, caving of the upper rock mass occurs, and the caving block is small as a whole; it is not easy to induce large-scale overall caving, which can avoid the impact gas wave disaster. The repeated formation and dissipation of stress arches make the overlying strata of the goaf appear intermittent caving, and the development and connection of tensile damage in the overlying strata of goaf are the main reasons for the fracture development and caving of the overlying rock. Engineering practice has shown that this method is characterized by safety and low cost and can provide guidance and reference for the management of goaf under similar conditions.

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    Damage Evolution Characteristics of Saturated Sandstone in Freeze-Thaw Cycles
    Tao XU, Jing-chang QIU, Yang YUAN, Bin XU
    2025, 46 (10):  132-142.  DOI: 10.12068/j.issn.1005-3026.2025.20240070
    Abstract ( 118 )   HTML ( 1)   PDF (5987KB) ( 22 )  

    To reveal the deformation and damage mechanism of rock in cold region rock engineering under freeze-thaw cycles, the porosity changes and macroscopic strength mechanical properties of saturated sandstone were analyzed through laboratory freeze-thaw cycle tests, low-field nuclear magnetic resonance experiments, and acoustic emission (AE) monitoring. A coupled temperature, permeability, stress, and damage model for saturated rock under freeze-thaw cycles was developed and validated. Numerical simulations were carried out to investigate the porosity variation and damage evolution in saturated sandstone subjected to different freeze-thaw cycles. The results indicate that as freeze-thaw cycles increase, the porosity growth rate of sandstone increases, while the uniaxial compressive strength decreases, and the rate of strength reduction gradually accelerates. The changes in pore size and quantity lead to deterioration in the strength of sandstone. Freeze-thaw-induced damage in sandstone arises from the combined effects of freeze-thaw cycles and loading, with the damage variable eventually approaching 1 as strain increases. The findings offer theoretical insights and experimental data for understanding the mechanical characteristics of rocks in cold regions.

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    Experimental Study on Ground Pressure Control Mechanism in Continuous Mining of Gently Inclined Thin Veins
    Kun-meng LI, Zheng-rong LI, Zhi-peng XIONG, Yuan-hui LI
    2025, 46 (10):  143-150.  DOI: 10.12068/j.issn.1005-3026.2025.20240082
    Abstract ( 173 )   HTML ( 2)   PDF (10744KB) ( 12 )  

    To address low productivity, high ore loss, and frequent rock hazards in traditional room-and-pillar and breasting mining methods for gently inclined thin veins, laboratory similarity experiments were conducted for multi-stope mining of gently inclined thin veins at Sandaogou gold mine using novel pre-stressed expandable pillars technology. Surrounding rock deformation, stress distribution, fracture evolution, and roof failure modes were analyzed under unsupported and pre-stressed expandable pillar-supported conditions. Results show that compared with the unsupported condition, the pre-stressed expandable pillars can reduce the roof deformation by approximately 44%, relieve stress release in shallow goafs, and mitigate stress concentration in deep strata/floor pillars. The surrounding rock only experiences local instability, effectively avoiding the sudden collapse of the roof. This provides theoretical support for the stability control of the surrounding rock during the continuous mining of gently inclined thin veins.

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