Direct reduction is the most promising process for the treatment of ilmenite, with the general formula Fe1+yTi1−yO3. The phase transformation behavior of ilmenite during reduction not only holds significant theoretical value but also has important implications for the industrial application of direct reduction. The variation in iron content among ilmenite ores from different mines leads to differences in Fe(III) content, which in turn affects the phase transformation behavior during H2-based direct reduction. In this study, ilmenite samples with varying Fe(III) contents were synthesized, and both synthetic and natural samples were reduced in hydrogen to investigate their phase transformation behaviors. It was found that the Fe(III) content in the ilmenite lattice, represented by the 2y value, plays a critical role in determining the phase transformation behavior during reduction. Depending on the Fe(III) content, three distinct phase transformation pathways were observed: when 2y = 0, the transformation path is FeTiO3 → FeTi2O5 → TiO2; when 0 < 2y < 2/3, the path is Fe1+yTi1−yO3 → FeTiO3 + Fe2TiO4 → FeTiO3 → FeTi2O5 → TiO2; and when 2/3 < 2y < 2, the path is Fe1+yTi1−yO3 → Fe2+xTi1−xO4 → Fe2TiO4 → FeTiO3 → FeTi2O5 → TiO2.

Vanadium is a strategically important transition metal widely applied in steelmaking, chemical processing, and emerging energy-storage technologies. Although vanadium-bearing shale constitutes a major vanadium resource and is extensively distributed in several regions worldwide, its complex mineralogical assemblages and the strongly lattice-bound nature of vanadium impose significant challenges for conventional leaching routes. These constraints often lead to excessive acid consumption, limited leaching efficiency, and notable environmental burdens. To overcome these limitations, this study investigates oxalic acid leaching under autoclave conditions to enhance vanadium dissolution from vanadium-bearing shale. The key leaching parameters—including temperature, liquid-to-solid ratio, leaching time, and oxalic acid concentration—were optimized through single-factor experiments combined with an L9(34) orthogonal design. Furthermore, the leaching kinetics were analyzed using classical shrinking-core models, and the phase evolution of leaching residues was examined by X-ray diffraction (XRD). The results show that the optimal leaching conditions are 120 °C, a liquid-to-solid ratio of 3.0 mL/g, a leaching time of 5 h, and an oxalic acid concentration of 2.5 mol/L, under which the vanadium extraction efficiency reaches approximately 98%. Kinetic analysis reveals that the leaching process is predominantly controlled by interfacial chemical reactions, with an apparent activation energy of 54.9 kJ/mol (100–120 °C). Moreover, a portion of the oxalic acid in the leachate can be effectively recovered via low-temperature crystallization; cooling at 5 °C for 1 h achieves a recovery of 30.7%, enabling its reuse in subsequent leaching cycles. Overall, this study establishes an efficient and environmentally benign route for vanadium extraction from shale and provides both theoretical guidance and practical support for the sustainable utilization of vanadium-bearing resources.

Angle misalignment error and center distance deviation are inevitable imperfections in gear transmission systems. These two faults frequently coexist, directly affecting the time-varying mesh stiffness (TVMS) and, consequently, the vibrational response of the gear system. Establishing a gear TVMS model that accounts for the coupling effect between angle misalignment error and center distance deviation is crucial for the early design and subsequent fault diagnosis of gear transmission systems. This paper establishes a gear TVMS model that accounts for the coupling between angle misalignment error and center distance deviation. The accuracy of the proposed model is validated through finite element simulations. Using the proposed stiffness model, we investigate the respective influence of each individual fault on the meshing stiffness. The variation trend of meshing stiffness with backup ratio under fault conditions is quantitatively analyzed, and a design strategy is proposed—setting the backup ratio between 2.5 and 3.5—to mitigate the effects of these faults. A comparative study was conducted on the influences of the coupled fault and the individual single faults on the mesh stiffness. The results show that the influence of the coupled fault on the meshing stiffness of the system is manifested as a nonlinear combination of the influences of single faults. Furthermore, this nonlinear characteristic becomes more pronounced as the severity of the faults increases. In the case study in this paper, the difference between them reaches 18.71

In recent years, the direct reduction-melting separation process has attracted widespread attention for vanadium titanomagnetite (VTM). During the melting separation process, fluxes are commonly used to enhance the metallurgical properties of the slag. However, the fluxes not only increase production costs but also complicate the Ti/V-rich phases in the slag, making their extraction more challenging. In this study, VTM was directly reduced with hydrogen (H2). The degree of reduction was controlled by adjusting the reduction time, resulting in three distinct stages: Fe + FeTiO3, Fe + FeTi2O5, and Fe + TiO2. The corresponding actual metalization rates of iron were 86.15, 93.31, and 99.87 pct, respectively. Subsequently, the reduced products from these three stages were flux-free melted in an induction furnace, and their melting separation behavior, slag metallurgical properties, mineral composition, and the occurrence phases of Ti and V were investigated. The results showed that a flux-free melting and separation process is feasible when VTM is reduced to the FeTi2O5 stage. At the FeTi2O5 stage, the slag had a melting point of 1724 K and a viscosity of 0.06 Pa s at 1873 K. The reduction and melting times required were relatively short, and the slag-metal separation was excellent, with Ti and V almost entirely enriched in the slag. The content of Ti and V in the slag was the highest at this stage, and the slag contained only pseudobrookite, spinel, and silicate phases. Among these, pseudobrookite was the only Ti/V-enriched phase, exhibiting a regular morphology, large grain size, and clear boundaries with the other two phases.

Rebar is a critical material in concrete constructions like high-rise buildings and seismic-resistant structures. To enhance its properties, microalloying with nitrogen is employed, but traditional methods using micro alloy additives such as vanadium (FeV), niobium (FeNb), titanium (FeTi), and vanadium nitride (VN) face issues of high costs, reduced purity, and difficulty in controlling molten steel composition. This article presents a novel approach of injecting top-blown O2–N2 mixed gas to increase nitrogen content efficiently. Experiments simulated HRB400 steel samples, varying N2 ratios (10%, 20%, 30%, 40%), temperatures (1500 °C, 1550 °C, 1600 °C), and blowing times (1, 2, 3 min). Results show that optimized parameters enable nitrogen content adjustment from 50 to 104 ppm, with nitrogen utilization improved to 5.4%. This method utilizes inexpensive N2 gas, reduces impurities, and provides precise control, offering a cost-effective and sustainable solution for high-performance steel production by replacing costly alloys and meeting nitrogen requirements.

Based on our previous report that Fe-Si-MEL zeolite could behave as a potential bi-functional material for removing VOCs under a humid environment, it adsorbs VOCs with its low hydrophilic nature. It then catalytically oxidizes VOCs followed by catalytically oxidizing VOCs to CO2 and H2O. In this work, the synthesis process of Fe-Si-MEL was tracked to investigate the critical importance of zeolitic framework formation on both the adsorption and catalytic oxidizing ability of toluene as a typical VOCs molecule. It was found the saturation time of toluene adsorption increased by 4.16 times, corresponding to the saturation adsorption capacity increasing by 6.96 times with the increase of the relative crystallization data from 28.50 % to 100 %. Adsorption kinetic fitting analysis results indicate that the adsorption of toluene on Fe-Si-MEL zeolite is a complex physical-chemical adsorption process, which is closely related to both framework integrity and Fe species. Once the framework is formed, the adsorption behavior is a process jointly controlled by external and internal diffusion. As Fe-O-Si zeolitic framework was formed, the temperature of toluene oxidation (T90) decreased from 400 degrees C to 318 degrees C. Various techniques were applied to characterize the variation of physicochemical properties with the increase of zeolitic framework integrity. Correlation analysis demonstrated that the adsorption capacity of zeolite is closely related to the improvement in porosity with increase of zeolitic framework integrity, while the significantly increased tetra-coordinated framework and hexa-coordinated extra-framework iron species involved in zeolite structure greatly contribute to both acid sites and active oxygen species, thus significantly enhancing the oxidizing ability. Taken together, these findings underscore the importance of zeolitic framework formation in optimizing the dual functionality of Fe-Si-MEL for effective VOC removal.

This study conducted hydrogen enriching and releasing experiments on stainless steel X17CrNi16-2 in a vacuum tube furnace. The results showed that at 1823 K and hydrogen pressures of 0.06, 0.08, and 0.10 MPa, hydrogen mass fraction in the steel reached 18.5 × 10−6, 20.1 × 10−6, and 22.5 × 10−6, respectively. During vacuum treatment at pressures of 0.02, 0.03, and 0.04 MPa, hydrogen release lasted 5 minutes, with hydrogen mass fraction reaching 11.1 × 10−6, 13.4 × 10−6, and 15.5 × 10−6. Both the hydrogen enriching and releasing processes approached equilibrium approximately and conformed to Sievert's law. In the initial 80 pct stage of hydrogen enriching, the rate was controlled by hydrogen mass transfer within the steel, with a mass transfer coefficient of 0.144 cm/s. In the final 20 pct stage, a combination of the interfacial chemical reaction and hydrogen mass transfer controlled the rate, with the interfacial reaction playing a larger role, was addressed. During the hydrogen releasing experiments, the appearance of bubbles in the first minute made the kinetic integral equations inappropriate for data fitting, and hydrogen mass transfer within the steel was the rate-limiting step. After the first minute, the hydrogen release rate significantly decreased, controlled by a combination of hydrogen mass transfer and the interfacial chemical reaction, with hydrogen mass transfer being dominant. The equilibrium constant KH for the reaction 1/2H2 → [H] was significantly lower than 1, suggesting that the rate constant for the forward reaction kR was substantially smaller than the rate constant for the reverse reaction kR−, as described by the relationship KH = kR/kR−. This suggests that the latter stages of hydrogen enriching are more likely to be controlled by the interfacial chemical reaction, whereas hydrogen releasing is less likely to be influenced by this factor.

In the present study, silicon carbide (SiC) was prepared via carbothermal reduction method using carbonaceous vanadium -bearing stone coal at 1400 degrees C. Compared to other reported raw materials, SiC was prepared at a relatively low the reaction temperature. The effects of temperature, duration and vanadium catalysis on the process of SiC preparation were investigated, and the kinetics of SiC nucleation and growth were analyzed. The results indicate that the SiC conversion of samples with 0 wt% and 2 wt% V2O3 additions reached to 68.9 wt% and 80.7 wt% at 1450 degrees C for 5 h. It was observed that the reduction of vanadium oxides resulted in the formation of vanadium carbide (VC), which played an important role in catalyzing the nucleation of SiC and accelerating its growth. The mechanism of SiC nucleation and growth is consistent with the Johnson-Mehl-Avrami-ErofeevKolmogorov (JMAEK) model, and the apparent activation energy values of the carbothermal reduction reaction are 213.17 kJ/mol and 109.66 kJ/mol for samples with 0 wt% and 2 wt% V2O3 additions. Therefore, this method not only expanded the source of raw material but also reduced energy consumption and economic costs.

The aim of the present study is to investigate the solubility of nitrogen in super or hyper duplex stainless steel, which is characterized by a very high Cr content, as well as the activity interaction parameters between N and other alloy elements. The chemical equilibrium method was employed in the present experiment. High Cr, Ni, and Mo content Fe−Cr−N−O and Fe−Cr−Ni−Mo−N−O melt are equilibrated at 1873 K under atmospheres of pure nitrogen and Ar/N2 gas mixture. The melts were placed in Al2O3 crucibles and coated with graphite crucibles. The experimental results showed that the solubility of N significantly increased with increasing Cr content, reaching over 1 wt pct at a Cr content of about 40 wt pct. In addition, the solubility of Cr increased slightly with a decrease in Ni content and an increase in Mo content. The activity interaction parameters were fitted using WIPF (Wagner’s Interaction Parameter Formalism), as shown as follows: eNCr=−0.07083, rNCr=+0.0005888, rNN=−0.00926, eNNi=+0.30885, rNNi=−0.03963, eNMo=−0.05882, rNMo=+0.00616; the comprehensive set of thermodynamic basic parameters obtained in this study can be effectively used to assess the N solubility in USSD with a Cr content exceeding 30 wt pct.

In the present study, a process of separating high-quality TiO2 from an oxalic-acid leachate of vanadium slag was proposed. It consists of two steps; oxalic acid was firstly recovered from the leachate by the cooling-crystallization method, and subsequently TiO2 was separated from the oxalic-acid recovered leachate by the hydrothermal precipitation method. The experimental results indicate that oxalic acid can be recovered from the leachate by cooling crystallization at 5 °C, and after the recovery of oxalic acid, the purity of final TiO2 product can also be improved. For example, when the leachate was cooled directly at 5 °C for 5 h, about 7% of oxalic acid was recovered, and the purity of final TiO2 product improved from 95.7% to 96.6%. Furthermore, it was found that when some HCl solution was added to the leachate, both the recovery percentage of oxalic acid and the purity of TiO2 product increased. For instance, when 15 vol% of HCl solution relative to pregnant leachate was added, about 35% oxalic acid was recovered by cooling crystallization at 5 °C for 3 h, and the anatase TiO2 product with a purity of 99.2% was obtained by hydrothermal precipitation at 140 °C for 2.5 h.

Catalytic combustion is one of the most effective technologies applied to volatile organic compounds (VOCs) emission control, in which zeolites have been regarded as a unique support or even a catalyst due to their unique shape & size features as well as the interaction between the zeolitic structural groups and the extraneous metal species. Particularly, Mn-based zeolites have attracted great attention as a promising catalyst for their superior redox ability on account of mixed valent properties. In this work, a series of Mn-contained samples with different compositions were synthesized to investigate the role of Al and Mn in zeolite for catalytically combusting VOCs. As redox active sites, Mn is well dispersed in the form of oligomeric Mn oxide clusters on the surface to optimize catalysis. With Al and Mn introduced into zeolite simultaneously, more defects for the activation of adsorbed oxygen appeared on superficial MnOx, but Al prevented Mn being incorporated in ZSM-11(MEL) distinctly, which is a principal factor affecting the catalytic activity. Additionally, Pt was introduced to further enhance the catalytic performance, whose function in Mn-MEL was also clarified in detail via XPS and other characterization techniques. Results demonstrated that appropriate Mn/Pt ratio could create suitable surface morphology (the interface of Pt-MnOx) for the adsorption of oxygen species via the synergistic catalytic effect caused by Pt and Mn.

To improve the surface tribological properties of TC4 titanium alloy, three kinds of micro textures have been processed on the surface of TC4 titanium alloy by picosecond ultraviolet laser technology. The tribological properties of the textured TC4 titanium alloy under multi-contact conditions were investigated by multifunctional friction and wear testing machine. The surface hardness, surface roughness, three-dimensional profile and morphology of wear marks of textured TC4 titanium alloy were analyzed by microhardness tester, scanning electron microscope and laser confocal microscope. The results reveal that the surface hardness of textured TC4 surface increases by about 60%, and the triangular textured surface shows the highest hardness. Micro texture effectively reduces the friction coefficient of the TC4 surface. The circular and rectangular textured surfaces indicate the lowest friction coefficient, about 10% lower than that of non-textured surface. Capable of capturing the wear debris, the micro texture can reduce abrasive wear and improve wear resistance. Under the same contact conditions, the wear volume of textured samples is reduced by about 50% compared with no-textured surface. When the load is constant, the friction coefficient of textured TC4 surface decreases with the increase of velocity. Under the same wear speed, the lower load leads to a decrease of friction coefficient on the textured TC4 surface. This study presents an effective way to improve the tribological properties of titanium alloy, providing an alternative way to reduce the loss and failure caused by the friction and wear on titanium alloy.

Spontaneous emulsification phenomena at 1873 K for the interfacial reaction between high-Al steel and CaO–SiO 2 flux was reevaluated. A mild spontaneous emulsification phenomenon was observed, which intensifies with the increase of Al content. The Al mass transfer in alloy along with the Al 2 O 3 mass transfer in slag was assumed to control the global reaction, which was validated by fitting results. The mass transfer coefficient of Al 2 O 3 in slag, k_(Al_2O_3) , was determined to be 2.73 × 10 –6 .

For the purpose of determining the interaction parameters between Mn and Al, and the influence of Mn on Al2O3 inclusions formation in the Fe-Mn-Al-O melts with high Mn and Al contents, three groups of Fe-Mn-Al-O melts with the initial Al content of 3, 5, and 7 mass% and different Mn contents were equilibrated with pure solid Al2O3 in an Al2O3 crucible at 1873 K and Ar-H2 atmosphere. Then, the interaction parameters between Mn and Al were deduced using the WIPF (Wagner’s Interaction Parameter Formalism) and the R-K polynomial (Redlich-Kister type polynomial), respectively. From the WIPF, the first- and second-order interaction parameters, eAlMn and rAlMn, were determined to be 0.0292 and −0.00016, respectively. From the R-K polynomial, the binary interaction parameters, ΩMn-Al0 and ΩMn-Al1, were determined to be 73,439 J/mol and −34,919 J/mol, respectively. The applicability of the WIPF to high Mn and Al content Fe-Mn-Al-O melts was investigated by comparing the Al activity calculated by the WIPF and the R-K polynomial using the obtained data. The results showed that WIPF can be used in high Mn and Al content melts in the current concentration range. Further from the iso-activity contours of Al, the activity of Al increases with increasing Al or Mn content. Finally, the thermodynamic calculations show that the addition of Mn decreases the equilibrium O content at the same Al content, making the formation of Al2O3 inclusions easier.

Although vanadium slag contains various valuable metals, including vanadium, titanium, chromium, iron, etc., it is only used to extract the vanadium due to technical limitations. In order to realize the comprehensive utilization of vanadium slag, a new approach was proposed in this work. First, the hydrogen reduction of vanadium slag was investigated. The phase and micromorphology evolution of the vanadium slag under different reduction conditions were discussed in detail. The results showed that the pyroxene and olivine surrounding the spinel in vanadium slag were reduced selectively into metallic iron and silica under appropriate reduction conditions, and the structures were destroyed. Then, the method of recovering metallic iron from the reduced vanadium slag with ferric chloride solution was investigated. The results showed that more than 98 pct of metallic iron in the reduced vanadium slag can be leached selectively by ferric chloride solution, and the vanadium, titanium, and chromium were left in the deironized intermediate. Finally, the extraction of vanadium, titanium, and chromium from the deironized intermediate by the oxalic acid hydrothermal leaching method was studied, and the leaching recoveries were 96.8, 94.7, and 95.4 pct, respectively. This approach provides insights into the comprehensive utilization of vanadium slag, which is especially favorable for low-grade vanadium slag.

To understand the reaction mechanism between high Mn-high Al steel and slag, the reaction experiment of Fe-Mn-Al melts with CaO-SiO2-type flux was carried out in MgO crucible at 1873 K. The evolution of the morphology of interface was inspected firstly, and then the global reaction kinetics was modeled in consideration of the effect of dynamic interfacial phenomena. The results show that in the reaction of Fe-5 mass % Al alloy with high SiO2 or low SiO2 protective slag, the strong chemical affinity between the metal and flux leads to strong spontaneous emulsification and attenuated with the progression of the reaction. Combined with the change of interfacial area caused by emulsification, it is found that the global reaction kinetics can be described satisfactorily by the mass transfer model of Al in liquid steel, and the determined mass transfer coefficient was about k[Al]=4.46×10−5 m/s. However, the emulsification phenomenon in the reaction of Fe-13%Mn-5%Al alloy with low SiO2 slag did not disappear with the reaction, which can be attributed to the decreasing of the interfacial tension with Mn addition and the accumulation of C on the interface. This reaction process can be modeled by assuming the mass transfer of SiO2 in the slag as the rate-controlling step with the estimated transfer coefficient of k(SiO2)=5.12×10−6 m/s.

(Sm1-xGdx)(2)Zr2O7 (0 <= x <= 1) ceramics, a new thermal barrier coating material, are commonly synthesised by chemical coprecipitation and calcination methods. However, when using the chemical coprecipitation method to synthesise ceramic powder, a large amount of strong acids and ammonium hydrate are consumed, leading to environmental pollution and restricting the production of new ceramics. Thus, a cleaner one-step hydrothermal synthesis method is proposed to synthesise (Sm1-xGdx)(2)Zr2O7 (0 <= x <= 1) thermal barrier coating ceramic powders, which avoids the use of strong acids and reduces the use of ammonium hydrate. Using this cleaner method, pure (Sm1-xGdx)(2)Zr2O7 ceramic powders were synthesised with particle sizes smaller than 1 mu m. Subsequently, bulk ceramics were prepared, and the thermophysical properties of the bulk ceramics were determined. The results show that the thermal expansion coefficients of the ceramics changed slightly after 1300 K, and the coefficient values of the ceramics were approximately 11 x 10(-6) K-1 at 1300 K. The thermal conductivities were in the range of 0.95-1.4 W m(-1) K-1 from 700 K to 1500 K, which is slightly smaller than that of the ceramic synthesised by the chemical coprecipitation method. These results show that the thermophysical properties of the (Sm1-xGdx)(2)Zr2O7 bulk ceramics synthesised using ceramic powders are satisfactory, further demonstrating that the hydrothermal synthesis process designed in the present study is feasible.

Aiming at alleviating the difficulties of extracting vanadium from high-carbon stone coal and solving the relevant pollution problem, a new synergetic and cleaner method combining concentration of vanadium with clean utilization of carbon was proposed and corroborated. Firstly, Fe2O3, acting as the source for the catalytic of carbon gasification and the capturer of vanadium, was added to the raw ore. Then, the carbon within the raw ore was gasified by water vapor at 800-900 degrees C under the catalysis of reducing product of Fe2O3 (Fe3O4) to generate synthesis gas (CO + H-2), and subsequently the vanadium dispersive occurred in the ore was captured by Fe3O4 at 1100-1200 degrees C under Ar atmosphere to form FexV(3-x)O(4). Finally, the FexV3-xO4 phase was separated magnetically, and a high-grade vanadium concentrate was obtained. The experimental results show that the Fe3O4 effectively promoted the gasification rate and ratio of carbon. When 10 mass% Fe2O3 relative to raw ore was added and roasted at 850 degrees C for 2 h, the gasification ratio of carbon increased by 26%. The gasification ratio of carbon could reach up to 90.2%. Besides, the Fe3O4 could react with the V3+ components to form magnetic V-rich phase, FexV3-xO4, and the vanadium concentrate was obtained by magnetic separation. Under the optimal conditions, the vanadium concentrate with a metallic vanadium content of 6.35 mass% was obtained by magnetic separation, which was 23.5 times higher than the raw ore. The recovery ratio of vanadium reached 85.6%.

Deep mining is an inevitable trend in the exploitation of metal resources owing to their increasing demand. The multifield coupling environment for deep mining, which includes a high in situ stress, high temperature, high hydraulic pressure, and strong disturbances from excavations, pose considerable challenges to mining safety and efficiency. Intelligent or smart mining is a key to revolutionizing the mining industry. Therefore, for promoting the intelligent transformation and upgrading of the mining industry, the study of intelligent mining technologies for deep mines has a considerable strategic significance. Based on the strategic background of mining deep resources, this study investigated future technological strategies for exploiting deep metal resources toward 2035. Global technological trends on deep intelligent mining subject to multifield couplings were analyzed using technological forecasting methods. Hot research topics and advanced technologies related to intelligent deep mining subject to multifield couplings were obtained. Based on experts’ opinions and analyses, key fundamental theories and techniques for intelligent deep mining toward 2035 were proposed. There are three promising mining methods: unconventional deep mining methods without blasting, continuous pastes backfill mining in deep mines, integration of mining, mineral beneficiation and backfill. Advanced technologies can be divided into three types: (1) smart perception of the deep mining environment, (2) intelligent working during deep mining, and (3) intelligent control of mining systems. Type 1 includes intelligent in situ stress measurements, the intelligent identification of rock mass structures, microseismic monitoring and early warning of disasters, intelligent underground space exploration, and intelligent perception of man–machine systems. Type 2 includes intelligent full-section well excavation equipment, intelligent support technology and equipment, intelligent continuous mining technology and equipment, unmanned intelligent mining equipment, and intelligent lifting technology and equipment. Type 3 includes the intelligent control of the filling system, intelligent control of the microclimate in tunnels, flexible data communication on working faces, intelligent scheduling for the entire life cycle of deep mining, intelligent scheduling of the entire mining process, integrated platform for mining management, and big data analysis for deep mining. Technological strategies, key tasks, and a technical roadmap for 2035 were proposed for intelligent deep mining subject to multifield couplings in China, including development targets and demands, fundamental research areas, and key technologies and equipment. Technological development procedures to transform deep mining technologies and improve mining intelligence were presented. Some suggestions were provided in terms of policies, industries, technologies, and talent for intelligent deep mining.

针对深部开采下巷道稳定性问题,以某铅锌矿568 m水平中段巷道为工程背景,通过支撑结构理论计算模型,结合FLAC3D数值模拟实验,揭示不同岩体质量等级下巷道承载结构分布特征,分析岩体质量等级对各承载结构区域下最大、最小主应力分布及塑性破坏特征的影响.研究发现:①岩体质量等级每提高一级,浅、深和关键支撑层厚度分别平均增加0.43、0.65、0.21 m,该矿深部巷道的浅、深和关键支撑层厚度分别在0.42～0.85、2.31～3.08、0.46～1.02 m之间;②随着岩体质量等级的增加,各支撑层内最大、最小主应力值呈增加趋势,不同区域内应力分布具有明显的差异性;③关键支撑层外边界到巷道边界之间的围岩会发生塑性破坏;围岩强度较低时,浅部支撑层内巷道底板及拱角容易出现拉伸破坏,这导致部分巷道出现底角破碎、两帮岩体沿节理面破坏的现象.岩体质量等级越高,关键支撑层离巷道越远,塑性破坏范围越大.