Advances in Engineering Research : Possibilities and Challenges
Advances in Engineering Research : Possibilities and Challenges ISSN Print: 3079-5192 ISSN Online: 3079-5206
Feasibility and Challenges of Ultrafine Stone Powder and Fly Ash Composite Grouting Material
Coal mining and coal-fired power generation produce large quantities of coal-based solid wastes such as fly ash and coal gangue, whose accumulation occupies land and poses environmental risks. Meanwhile, ultrafine stone powder, as a byproduct of stone processing, faces similar challenges in resource utilization. The combination of these two types of solid wastes to prepare grouting materials has become an important research direction in fields such as bed-separation grouting for subsidence reduction and goaf filling treatment. This paper systematically analyzes the feasibility basis of ultrafine stone powder and fly ash composite grouting material, including the strong impetus from national policies on solid waste resource utilization, significant reduction in raw material costs, and the complementary performance advantages of the composite system in terms of fluidity regulation, stability improvement, and strength enhancement. At the same time, it deeply discusses the multiple challenges faced by this material, covering the difficulty of matching slurry rheological behavior with bed-separation space, the deterioration of filling quality caused by water separation, the risk of groundwater pollution from heavy metal leaching, and the precise matching between grouting timing and filling effectiveness. The research indicates that this composite material has broad prospects for engineering applications, but its large-scale promotion still requires continuous technical breakthroughs in formulation optimization, environmental risk control, and engineering adaptability.
Copyright (c) 2026 by author(s) and Erytis Publishing Limited. https://creativecommons.org/licenses/by/4.0/
Mechanisms and Control of Accumulated Plastic Deformation in Highway Subgrades for Durable Service
Under long-term cyclic traffic loading, subgrade soils may develop accumulated irrecoverable plastic strain, which gradually evolves into permanent deformation affecting pavement smoothness, bearing capacity, and durability. Compared with construction-stage compaction quality, permanent deformation of subgrades during operation can better reflect the long-term service risks of road structures under coupled loading–environmental effects. This paper systematically reviews the testing and characterization, influencing factors, prediction models, structural calculation methods, and control approaches for subgrade permanent deformation. The results indicate that water content, degree of compaction, cyclic stress, confining pressure, loading duration, rest period, and overburden static load jointly govern the development of permanent deformation. Existing constitutive models have a solid theoretical basis but are limited by computational efficiency in long-term cyclic analysis, whereas mechanical–empirical models are convenient for engineering applications but still face limitations in parameter calibration and generalization capability. Future research should strengthen the reproduction of service conditions, coupled moisture-field and stress-field analysis, and reliability-based control criteria, thereby providing a basis for durable subgrade design and maintenance decision-making.
Comparative Analysis on Mechanical Performance of Concrete Inclined Tension Rods with Square and Circular Steel Pipes in Cable-Stay Girder Anchorage Zone of Low-Pylon Cable-Stayed Bridge
Aiming at the inherent performance bottlenecks of reinforced concrete (RC) inclined tension rods in the cable-girder anchorage zone of low-pylon cable-stayed bridges, such as low ductility and significant post-peak damage localization, an optimized scheme of prestressed concrete-filled steel tube (CFST) inclined tension rod is proposed. Taking the Luzhou Tuojiang Railway Super Large Bridge, a low-pylon cable-stayed bridge with a span arrangement of (146+292+146) m, as the engineering background, a three-dimensional nonlinear finite element model is established based on ANSYS APDL. The whole-process mechanical behaviors of three schemes, namely RC, square CFST and circular CFST inclined tension rods, under the most unfavorable cable force are comparatively analyzed, and the influence law of section form on mechanical performance is revealed from the perspective of confinement mechanism. The results show that compared with the RC scheme, the ultimate bearing capacity of the two CFST schemes is increased by 115.3% and 124.2%, the initial secant stiffness is increased by 61.9% and 63.2%, and the displacement ductility coefficient is increased by 33.5% and 49.4%, respectively. The uniform circumferential confinement provided by the circular section completely eliminates the weak confinement area at the mid-span of the square steel tube wall, and the load rises steadily at the large deformation stage. The circular CFST scheme with a diameter of 560 mm, wall thickness of 16 mm, Q345 steel tube, C60 core concrete and confinement coefficient ξ=0.829 is recommended as the optimal design scheme. The research results can provide a reference for the engineering design of inclined tension rods in the cable-girder anchorage zone of low-pylon cable-stayed bridges.
The Rheological Properties of Recycled Asphalt With Pyrolysis Oil From Waste Plastics
To understand the regeneration effects of PEO and PPO regenerants on aged asphalt, this chapter studies the physical properties of the regenerated asphalt and finds that PEO and PPO can basically restore the performance of aged asphalt, but the improvement effects of PEO and PPO on base asphalt and SBS modified asphalt are different.
Research and Field Application of a Down-Dip Withdrawal Method for Heavy Fully Mechanized Hydraulic Supports in a Steeply Inclined Longwall Face
The down-dip withdrawal of heavy hydraulic supports under a large face inclination remains a bottleneck affecting the safety and efficiency of longwall face relocation. In this study, a down-dip withdrawal technology for heavy fully mechanized hydraulic supports was developed and field-tested at the 2091 working face of No. 6 Coal Mine, Hebi Coal Company. The coal-pillar layout during the closing stage was optimized to improve the coal recovery ratio and reduce resource losses. The pre-withdrawal support scheme, including a flexible-mesh artificial roof, was redesigned to enhance roof stability during the withdrawal period. The withdrawal process was also optimized to enable parallel operations of support alignment, loading and disassembly. Mechanized withdrawal equipment was introduced to address the anti-overturning and anti-sliding requirements during top-to-bottom transportation of fully mechanized supports, thereby realizing safe and mechanized support withdrawal. Field application showed that the face relocation time was reduced by 55%, while labor intensity, production cost and the risk of spontaneous combustion were substantially decreased.
Retrieval of heavy supports in coal mines
Research Progress on Dowel-Type Connection Joints of Timber Structure
Dowel-type connections (bolts, dowels, self-tapping screws, etc.) are the most widely used joint forms in modern timber structures, and their mechanical properties directly affect the load-carrying capacity and deformation behavior of the overall structure. This paper reviews the research progress of dowel-type timber connections from three aspects: load-carrying capacity calculation theory, numerical simulation methods, and innovative connection technologies with durability issues. In terms of load-carrying capacity theory, the Johansen yield model remains the core foundation of various design codes. Recent studies have extended this model to new engineered wood products such as cross-laminated timber and glued laminated bamboo, as well as to extreme conditions like fire. Regarding numerical simulation, the classical finite element method is the most mature approach, while the peridynamics method shows unique advantages in simulating wood cracking and fracture. For innovative technologies, self-tapping screw reinforcement and all-wood connections (dowel laminated timber, rotational welding, etc.) have become important development directions, but the water resistance of rotationally welded joints remains a critical issue. Current research still has gaps in the load redistribution mechanism of multiple-dowel connections and long-term performance under complex environmental conditions. This review aims to provide a reference for the design optimization and future research of dowel-type timber connections.
Adaptive Terrain-Cognizant Multispectral Vision and Distributed Intelligence for Low-Altitude Unmanned Systems in Yunnan Plateau and Canyon Ecosystems
The rapid expansion of the low-altitude economy across southwestern China necessitates autonomous unmanned aerial systems capable of sustained operations within deeply dissected topography and hyperdiverse ecosystems. This study presents a unified framework, designated LAVENS, that integrates terrain-cognizant adaptive visual odometry with hierarchical spectral attention networks to simultaneously address navigation robustness and ecological inference accuracy in complex Yunnan terrains. A terrain roughness adaptive factor is embedded within an extended Kalman filtering pipeline to modulate measurement noise covariance in real time, thereby mitigating scale drift during canyon traversal. Complementarily, a hierarchical spectral attention network processes ten-band multispectral tensors through scaled dot-product self-attention to resolve vegetation boundaries under heterogeneous canopy illumination. Edge-cloud orchestration, based on directed acyclic graph scheduling, ensures end-to-end latency remains below 150 milliseconds while conforming to low-altitude airspace traffic management protocols. Extensive validation spanning six altitudinal belts—from tropical rainforest to nival rock—demonstrates that the proposed methodology reduces absolute trajectory error by a mean of 41.3 percent relative to current open-source SLAM libraries, and improves mean intersection-over-union for canopy species segmentation by 18.7 percent over conventional encoder-decoder architectures. These findings establish a scalable software and hardware architecture for ecological logistics and infrastructure inspection within the low-altitude economic corridor of the Yunnan plateau.
Research Progress on Hydration Heat of Mass Concrete
Mass concrete is widely used in bridge pile caps, hydraulic structures, foundations of high-rise buildings, nuclear power projects, and large underground structures. Due to the large structural dimensions, the hydration heat generated inside concrete is difficult to dissipate rapidly, which often leads to a high early-age temperature rise and significant temperature difference between the interior and surface. When thermal deformation is restrained, thermal stress develops inside the structure. If the tensile thermal stress exceeds the early-age tensile strength of concrete, temperature cracks may occur, thereby affecting structural integrity, durability, and service safety. Based on previous studies, this paper reviews the research progress on hydration heat of mass concrete from the aspects of hydration heat mechanism, material and mix proportion control, construction temperature-control measures, temperature monitoring, and numerical simulation. Existing studies show that reducing the hydration heat of cementitious materials, optimizing the proportion of mineral admixtures, controlling placing temperature, adopting layered and block construction, strengthening thermal insulation and moisture curing, and using cooling pipes can effectively reduce peak temperature and internal-surface temperature difference. With the development of monitoring technologies and numerical methods, temperature control of mass concrete is gradually moving toward refinement, intelligence, and whole-process control..
Study on Multi-parameter Mechanical and Microstructural Characteristics of Mining-used Cement-based Grouting Materials
To investigate the reinforcement effects of two grouting materials, laboratory tests were conducted using ordinary Portland cement and ultra-fine cement as the test materials. Taking the consolidated bodies of cement-based grouts as the research objects, tests on slurry flow characteristics, uniaxial compressive tests on consolidated bodies, and scanning electron microscopy (SEM) tests were carried out to study the mechanical properties of cement-based grout consolidated bodies with different water-cement ratios. The test results show that the viscosity of ordinary cement-based grout decreases with the increase of water-cement ratio, while the bleeding rate increases accordingly. The uniaxial compressive strength of ordinary cement-based consolidated bodies decreased by 35.1%, 43.9% and 5.2% respectively with the increase of water-cement ratio. Meanwhile, the average cumulative acoustic emission ring counts of ordinary cement-based consolidated bodies decreased by 76.7%, 71.1% and 50.1% respectively with the increase of water-cement ratio. Compared with ordinary cement grout at the water-cement ratio of 1:1, ultra-fine cement grout has lower viscosity and bleeding rate, and its consolidated body exhibits higher uniaxial compressive strength and larger cumulative ring counts. Analysis of SEM micrographs reveals that the ultra-fine cement consolidated body has fewer internal defects, more stable structure and stronger bearing capacity. The above test results indicate that ultra-fine cement can achieve significantly better reinforcement performance as a grouting material than ordinary Portland cement.
Mechanical Properties of Consolidated Bodies
Research Progress on the Seismic Behavior of Steel-Connected Precast Concrete Beam-Column Joint
Precast concrete frame structures have attracted increasing attention because they can improve construction efficiency, reduce on-site wet work, and support industrialized building production. In seismic regions, however, the reliability of beam-column connections remains a key factor controlling the load-transfer mechanism, deformation capacity, energy dissipation, and post-earthquake safety of the structural system. Steel-connected precast concrete beam-column joints introduce steel components into the joint region or beam-end connection zone, thereby changing the stiffness distribution, damage evolution, and hysteretic behavior of conventional precast joints. Based on existing studies, this paper reviews the research progress on precast concrete beam-column joints, steel-concrete composite beam-column joints, finite element simulation, and restoring-force models. The results show that considerable progress has been made in experimental investigation, connection-detail optimization, parameter analysis, and hysteretic model development. Properly designed precast and steel-concrete composite joints can achieve satisfactory bearing capacity, ductility, and energy dissipation, while numerical methods provide an effective means for extending limited test results to broader parameter ranges. Nevertheless, research specifically focused on steel-connected precast concrete beam-column joints remains insufficient, especially regarding low-cycle reversed loading behavior, unified design methods, and restoring-force models consistent with their actual damage mechanism. Future studies should strengthen full-scale cyclic tests, refined numerical modeling, and frame-level seismic performance evaluation.
Research Progress on the Seismic Behavior of Weak-Axis Beam-to-Column Connections of H-Shaped Steel Columns
Weak-axis beam-to-column connections of H-shaped steel columns are important force-transferring components in steel frame structures, and their mechanical behavior directly affects structural load-carrying capacity, deformation capacity, and seismic safety. Compared with strong-axis connections, weak-axis connections mainly transfer beam-end moments through the column web and its adjacent region. Owing to the relatively low out-of-plane stiffness of the column web and insufficient restraint of the panel zone, these connections are prone to local deformation, stress concentration, insufficient rotational stiffness, and uncertain plastic development. With the development of prefabricated steel structures and low- to mid-rise steel residential buildings, the seismic behavior of weak-axis connections has attracted increasing attention. This paper reviews existing studies from the aspects of experimental research, finite element analysis, moment-rotation relationship models, and new connection configurations. Previous studies show that end plates, T-shaped connectors, U-shaped connectors, I-shaped plates, column-tree splices, reduced beam sections, and local strengthening measures can improve load-transfer paths, enhance rotational stiffness and energy dissipation capacity, and move plastic deformation away from the column face. However, unified design methods, restoring force models, and prefabricated details still require further investigation.
Research on Surface Deformation Monitoring and Stability of Mined-out Areas Based on SBAS InSAR Technology
Long-term surface deformation over old mined-out areas overlain by thick unconsolidated strata in North China is prominent. Traditional monitoring approaches are difficult to achieve large scale, long time series, and high precision dynamic observations. To scientifically understand the spatiotemporal evolution of surface subsidence and site stability characteristics of old mined out areas, this paper takes the mined out areas of Panels 2301, 2302, and 2303 in the No.5 Coal Mine of Hebi Mining Group, Shancheng District, Hebi, Henan Province as the study object. Using the SBAS InSAR time series interferometric technique, 110 scenes of Sentinel 1A images from November 2015 to December 2024, combined with 30 m resolution SRTM DEM data and ESA precise orbit data, are adopted to invert the spatiotemporal distribution of annual average surface deformation rate and cumulative deformation over the past decade. Through time series subsidence curve analysis of typical monitoring points, profile comparison, and accuracy verification, the staged evolution and spatial differentiation of surface subsidence above goafs under thick unconsolidated strata are revealed. The results show that the study area is dominated by surface subsidence, with a maximum subsidence rate of −36 mm/a and an average rate of 2.35 mm/a. The spatial pattern of subsidence exhibits an obvious funnel shaped stepwise decrease. Around 2018, surface subsidence in the study area generally shifted from the rapid development stage to the residual deformation stage with slow attenuation. The attenuation rate shows significant spatial differences controlled by fault locations, panel conditions, and geological structures. Panel 2303, with a later stopping time, shows the most active subsidence, while Panels 2301 and 2302, mined earlier, have become basically stable. The SBAS InSAR results agree well with leveling measurements, and the monitoring accuracy meets the requirements for goaf stability evaluation. The findings can provide reliable technical support and scientific basis for land redevelopment, construction site selection, geological hazard risk assessment, and long term safety monitoring of old mined out areas in the Hebi mining area
Recent Advances in Quantitative Sensitivity Analysis for Dynamic Construction Control of Prefabricated Steel-Concrete Composite Cable-Stayed Bridges
Prefabricated steel–concrete composite cable-stayed bridges are a major form of industrialized bridge construction. Dynamic construction control and parameter sensitivity quantification are critical to ensuring structural safety and final alignment. Ultra-high-performance concrete (UHPC) has become a preferred material for precast segment connections due to its superior bond performance with reinforcing bars. This paper reviews recent advances in quantitative sensitivity analysis for dynamic construction control, focusing on the bond behavior of lap-spliced rebars in UHPC, key influencing parameters, and time-varying sensitivity characteristics. Research shows that steel fiber content, rebar diameter, lap length, cover thickness, and transverse reinforcement dominate bond strength and system sensitivity. The bond stress distribution along lap length varies significantly under different configurations, directly affecting structural stability during construction. Finally, existing challenges and future research needs are briefly discussed.
Prefabricated Steel–Concrete Composite Cable-Stayed Bridge
Research Progress on Fatigue Performance of Steel-Concrete Composite Structures
Steel-concrete composite structures integrate the superior tensile properties of steel and excellent compressive performance of concrete, which have been widely applied in long-span bridges, high-rise buildings, and industrial structures. Fatigue performance is one of the core control indicators for composite structures serving under long-term cyclic loads, such as vehicle traffic, wind excitation, and mechanical vibration. This paper systematically sorts out the latest research progress on the fatigue performance of steel-concrete composite structures in recent years. Firstly, the fatigue damage evolution mechanism of composite systems, including constituent materials and steel-concrete interface, is elaborated. Subsequently, the state-of-the-art experimental and numerical research on the fatigue behavior of typical composite members and key connectors is summarized. Then, the critical influencing factors, including material properties, structural details, service environment, and load characteristics, are comprehensively analyzed. Furthermore, the mainstream fatigue life evaluation methods and theoretical models are classified and discussed. Finally, the existing limitations of current research are pointed out, and the future research directions are prospected, aiming to provide reference for subsequent academic research and engineering application of steel-concrete composite structures.
State of the Art of Steel-Concrete Composite Bridge Towers with Steel Shells
As a high-performance steel-concrete composite structure, the steel shell concrete bridge tower integrates the advantages of high bearing capacity, excellent seismic performance, rapid construction and outstanding durability, and has become the mainstream structural form of bridge towers for long-span bridges in recent years. This paper systematically reviews the latest research progress of steel shell concrete bridge towers. Firstly, it summarizes the typical structural forms and construction technologies, and classifies the main failure modes under mechanical loads and thermal loads. Subsequently, it systematically discusses the influence laws of key parameters such as steel shell thickness, concrete strength, steel ratio, stud spacing and temperature field on the mechanical properties and interfacial bonding performance of the structure. Meanwhile, it sorts out the research status of thermal effects and long-term performance of steel shell concrete bridge towers. Existing studies show that the axial and eccentric compressive bearing capacity of the structure increases with the rise of steel ratio and concrete strength; reasonable stiffener configurations and shear connectors can significantly improve the interfacial bonding performance and inhibit crack propagation. The temperature field has a remarkable impact on the thermal stress of steel shell concrete tower columns, and hydration heat and solar radiation are the core control factors. Finally, this paper points out the deficiencies of existing research and prospects the future research directions including multi-field coupling theory, refined design method and prefabricated construction technology, so as to provide a reference for the engineering design and application of this structure.
Analysis of Functionalized Mode of Urban Building Facade Lighting
Le Corbusier once said, "Architecture is the brilliant, correct, and clever performance of assembled blocks under light, and the task of an architect is to bring the surface wrapped around the blocks to life." Architectural light is precisely one of the indispensable elements that "bring the surface to life.". The purposefulness and regularity of urban building facade lighting should be based on its functional use. As a functional lighting method, light transmission within buildings represents the aesthetic subject's recreation of the aesthetic object. It is also an important indicator for measuring the quality of urban buildings.
Engineering Biomimetic and Multifunctional Artificial Periosteum via Electrospinning for Bone Regeneration
This review delves into the advancements and strategies in electrospinning for the development of artificial periosteum in bone regeneration. Electrospun nanofibers offer advantages such as high surface area, porosity, and multifunctionality, making them suitable for mimicking the natural periosteum. The focus of this review lies in the recent progress in crafting electrospun artificial periosteum. It elucidates the histological structure and function of the periosteum, emphasizing its pivotal role in bone repair. Various materials, encompassing natural and synthetic polymers, are scrutinized for the design of effective artificial periosteum. Furthermore, it explores the utilization of diverse electrospinning process and other technologies such as phase separation and sol-gel method, which can be amalgamated with electrospinning for artificial periosteum development. Additionally, it delves into synergistic regulation of multidimensional osteogenic cues and the crucial osteogenic-angiogenic coupling effect for bone healing. In conclusion, limitations of current techniques and strategies are outlined, alongside future prospects for the application of advanced electrospinning technologies in the preparation of artificial periosteum.
Improved YOLOv11-Based Algorithm for Wood Surface Defect Detection
Wood surface defect detection is a critical process in industrial quality control. However, conventional deep learning models often struggle with complex periodic wood grain interference, extreme scale variations between micro-defects and large defects, and irregular defect geometries. To address these challenges, this paper proposes WSD-YOLO, an improved object detection algorithm based on YOLOv11n. First, an Enhanced Backbone (EB) is constructed by deepening the C3k2 modules to enrich multi-level feature representations, which improves the network's capacity to extract complex defect patterns. Second, a Transformer Attention Block (TAB) with an 8-head multi-head self-attention mechanism is integrated to model long-range spatial dependencies, effectively suppressing background texture interference from wood grains. Third, a BiFPN with P2 Enhancement (BPE) extends the feature fusion network to a four-scale bidirectional architecture, utilizing a high-resolution P2 branch (stride 4) to capture fine spatial details of micro-defects such as cracks and resin spots. Finally, a Decoupled Multi-Scale Head (DMH) separates the classification and localization branches to alleviate optimization conflicts caused by irregular defect boundaries. Experimental results on a custom dataset of 4,000 images across 7 defect categories demonstrate that WSD-YOLO achieves an mAP@0.5 of 74.34% and an mAP@0.5:0.95 of 39.24%, outperforming the YOLOv11n baseline by 0.82% and 1.51%, respectively. Notably, the detection precision reaches 72.18%, a 3.39% improvement over the baseline, confirming the model's superior capability in reducing false positives in complex industrial environments.
Improved YOLOv11n-Based Detection Algorithm for Railway Surface Defect Inspection
Railway surface defect detection is a critical component of automated track maintenance and safety assurance. Standard deep learning detectors face three domain-specific challenges in rail inspection: high visual similarity between de-fects and metallic rail surface texture, large spatial scale disparity across defect categories, and insufficient receptive field diversity for capturing large-area peri-odic corrugation patterns. To address these challenges, this paper proposes RSD-YOLO, an improved YOLOv11n-based detector incorporating three targeted structural modifications. First, Convolutional Block Attention Modules (CBAM) are inserted after the P3 and P4 backbone stages to provide multi-level dual-axis feature recalibration, suppressing metallic background noise and amplifying de-fect-discriminative activations. Second, BiFPN adaptive weighted fusion (BiFPN_Concat2) replaces standard PANet concatenation in the neck, enabling learnable asymmetric cross-scale feature interaction. Third, Atrous Spatial Pyra-mid Pooling (ASPP) with dilation rates {6, 12, 18} replaces the SPPF module at the backbone apex to provide parallel multi-receptive-field context aggregation without resolution loss. Experiments on a custom 8,000-image rail defect dataset of four categories demonstrate that RSD-YOLO achieves mAP@0.5 of 84.7% and mAP@0.5:0.95 of 64.8%, outperforming the YOLOv11n baseline by 3.8% and 3.4% respectively. Wheel Burn detection improves by 6.8% and Corrugation by 5.6%, confirming the model's effectiveness for the most diagnostically challenging defect categories in railway surface inspection.
Research Progress and Application Prospects of Bamboo-Wood Composite Structural Materials
Aiming at the dual challenges of high carbon emissions in the global construction industry and the shortage of high-quality structural wood resources in China, this paper systematically reviews the research progress of Cross-Laminated Timber (CLT), Hybrid Cross-Laminated Timber (HCLT), Laminated Veneer Lumber (LVL) and glued bamboo (Glubam), with a focus on analyzing the mechanical performance optimization and engineering application status of bamboo-wood composite structures. Studies have shown that although fast-growing poplar LVL can effectively improve the utilization rate of fast-growing wood, its mechanical properties are still difficult to meet the requirements of high-end structures; while Glubam glued bamboo has become an ideal structural reinforcement material due to its excellent strength-to-weight ratio and environmental protection characteristics. Based on this, this paper innovatively proposes a new bamboo-wood composite structure scheme using fast-growing poplar LVL as the core layer and high-performance Glubam as the reinforced outer layers. This scheme can give full play to the performance complementary advantages of the two materials and significantly improve the overall mechanical properties of the composite material. The research results provide a new idea for the high-value utilization of bamboo and wood resources in China, and have important theoretical significance and engineering value for promoting the sustainable development of the green building industry.
State of the Art of Bond Behavior of Lap Spliced Rebars in Ultra-High-Performance Concrete
Ultra-high performance concrete (UHPC) exhibits excellent mechanical proper-ties and superior bond performance with reinforcing bars compared with nor-mal concrete. Owing to its high bond strength, UHPC has attracted increasing attention in lap-spliced rebar connections. This paper reviews the bond behav-ior of lap-spliced rebars in UHPC. The main experimental methods and failure modes are first summarized. Then, the effects of key parameters, including steel fiber volume fraction, rebar diameter, lap length, clear spacing, cover thickness, and transverse reinforcement ratio, are discussed. In addition, the bond stress distribution along the lap length is reviewed. Existing studies indicate that the bond strength of lap-spliced rebars in UHPC increases with steel fiber content and cover thickness, while it generally decreases with increasing rebar diameter and lap length. Proper transverse reinforcement can restrain crack propagation and improve bond performance. The bond stress distribution also varies with lap length and exhibits different characteristics under different splice configura-tions. Finally, future research needs on the bond behavior of lap-spliced rebars in UHPC are briefly discussed.
Research Progress on the Static Behavior of Tubular Intersecting Joints
Tubular intersecting joints are key force-transferring components in tubular steel structures, and their static behavior directly affects the load-carrying capacity, deformation capacity, and overall structural safety. With the extensive application of tubular steel structures in long-span spatial structures, bridge engineering, transportation hubs, and industrial plants, research on the static behavior of tubular intersecting joints has continued to develop. Based on previous studies, this paper systematically reviews the existing research on static testing, finite element analysis, bearing-capacity and stiffness calculation methods, as well as strengthening measures for tubular intersecting joints. The results indicate that abundant achievements have been made in the study of joint failure modes, bearing-capacity laws, local stiffness, and spatial effects, and that these studies have provided important support for code revision and engineering design. However, considerable differences still exist among different joint types, loading conditions, and parameter ranges, and a unified design method for complex spatial joints and newly strengthened joints remains lacking. The review presented in this paper can provide a useful reference for future research and engineering applications of tubular intersecting joints.
State of the Art in Modified Asphalt Research for Highway Pavement Engineering
The purpose of this review is to systematically sort out the research status of modified asphalt, address the performance deficiencies of traditional asphalt pavements, and provide theoretical and technical support for its engineering application. Methods include synthesizing research progress of modified asphalt from 2020 to 2026, focusing on four main types of modifiers (polymer, nanomaterial, composite, and sustainable modifiers), and analyzing their effects on asphalt performance via key characterization techniques. Results show that different modifiers have distinct advantages: polymer modifiers improve high/low-temperature performance, nanomaterials enhance aging resistance and functionality, composite modifiers achieve synergistic effects, and sustainable modifiers realize environmental and economic benefits. Critical challenges such as poor modifier dispersion and high cost are also identified. Conclusions indicate that modified asphalt is pivotal for enhancing pavement durability, and future research should focus on solving existing challenges to promote its large-scale and high-quality application.
Numerical analysis of the mechanical state of subgrade filled with discarded phyllite with different stone content
To address the shortage of subgrade filling materials and the land occupation caused by engineering waste in highway construction in the Longnan area, phyllite waste generated from excavation sections and tunnel blasting was reutilized as subgrade fill. Heavy compaction tests were first conducted on phyllite mixtures with stone contents of 30%, 40%, 50%, 60%, and 70% to determine their compaction characteristics. The results showed that the maximum dry density was achieved when the stone content ranged from 50% to 60%, indicating favourable compaction performance. Subsequently, California Bearing Ratio (CBR) tests were performed on phyllite fills with stone contents of 40%, 55%, and 70% to evaluate their engineering applicability. Under different compaction conditions, the 55% stone-content mixture consistently exhibited higher CBR values and lower water absorption than the 40% and 70% mixtures, demonstrating superior bearing capacity and water stability. Furthermore, finite element models of subgrades filled with phyllite waste containing 40%, 55%, and 70% stone contents were established to analyse the mechanical response of the subgrade under static vehicle loading, dynamic vehicle loading, and the combined action of water infiltration and dynamic loading. The numerical results revealed that the maximum shear stress was concentrated at the side slope of the subgrade, while the maximum tensile stress occurred at the subbase layer of the pavement structure. Among the three cases, the subgrade filled with 55% stone-content phyllite exhibited the smallest settlement and lower tensile and shear stresses. Therefore, it is recommended that the stone content of phyllite fill be controlled within 50%–60% in practical engineering applications.
Data Analysis and Health Feature Construction for Lithium Battery Performance Testing
This study aims to conduct an in-depth analysis of lithium battery performance test data to reveal degradation patterns, enabling precise evaluation of battery health status and life prediction. In data collection, a multidimensional experimental framework was established based on NASA's standard battery aging dataset, systematically conducting feature mining and health factor extraction from charge-discharge data. By analyzing dynamic variations in parameters such as voltage, current, and temperature, combined with capacity increment analysis techniques, key features reflecting internal battery conditions were extracted. The research findings demonstrate that the constructed health features accurately reflect battery health status, which is crucial for ensuring performance, extending lifespan, and enhancing safety. These insights provide robust support for optimizing lithium battery applications across various scenarios.
Research on the Dynamic Forecast of Plug-in Hybrid Passenger Vehicle Market Sales Based on Multi-model Integrated Learning
The rapid development of the plug-in hybrid passenger car market has given rise to the demand for accurate sales forecasting. By constructing a multi-model integrated learning forecasting framework, SARIMA, LSTM, Prophet and XGBoost models are selected for integrated forecasting by combining sales and penetration data from 2021-2024. The experimental results show that the annual prediction error of the integrated model is 5.92%, which is significantly better than the 7.83%-9.37% of the single model. the validated prediction error in the first quarter of 2025 is less than 2.3%, confirming the practical value of the model. The forecast results show that the plug-in hybrid market penetration will reach 22%-24% in 2025, and annual sales are expected to reach 5.8-6.2 million units.
Green Pest and Disease Control Technology Systems and Their Integrated Application in Tea Plantations
Green pest and disease control in tea gardens is a crucial measure for reducing the use of chemical pesticides, ensuring tea quality and safety, and protecting the ecological environment of tea gardens. This paper systematically summarizes key technologies such as agricultural control, biological control, physical and chemical control, plant-based pesticides, and monitoring and early warning systems. It constructs an integrated technical model based on agricultural control, with biological control as the core, physical and chemical control as a supplement, and chemical control as a contingency measure, and proposes recommendations on scientific pesticide use, promotion mechanisms, and policies. Research indicates that the integrated application of green pest management technologies can effectively reduce pesticide usage, enhance tea quality, and improve the ecological environment of tea gardens. This paper serves as a reference for the promotion of green pest management in tea gardens and the sustainable development of the tea industry.
Research on Static Fracturing Roof Caving Technology for Hard Immediate Roof at the Open-off Cut of 15221 Fully Mechanized Mining Face in Hongliulin Coal Mine
Aiming at the engineering challenge that the hard immediate roof at the open-off cut of the 15221 fully mechanized mining face in Hongliulin Coal Mine is extremely prone to forming a large-area suspended roof and inducing dynamic strata pressure disasters during the initial mining period, this paper conducted an engineering experimental study on the static fracturing roof caving technology for hard immediate roofs. By drilling pre-splitting boreholes in the open-off cut and two gateways of the 15221 working face and injecting expansive cartridges, the roof caving characteristics, working resistance of supports, wind speed, and dust concentration changes before and after fracturing were analyzed. The results show that the static fracturing technology effectively severed the integrity of the hard roof, and the initial weighting step was controlled at 43.5 m. The over-limit ratio of support pressure dropped to 0.5%, effectively avoiding the risk of support crushing, and the average dust concentration in the working face was significantly reduced, achieving safe, efficient, and green roof caving.
Distribution Characteristics of the Overburden Three-Zone Structure in the Goaf of a Y-Type Ventilation Working Face
To elucidate the development law of the overburden three-zone structure in the goaf of a Y-type ventilation working face, the 32010 working face of a coal mine was selected as the engineering background, and the evolutionary characteristics of the overburden three zones were investigated by combining theoretical analysis with numerical simulation. First, the formation mechanism of the overburden three-zone structure was analyzed. Second, empirical formulae were employed to estimate the heights of the caving zone and fractured zone. Finally, a UDEC numerical model was established to simulate the evolution of overburden fractures during face advance. The results indicate that the theoretical calculation gives a caving-zone height of 10.24-14.45 m and a fractured-zone height of 37.86-51.04 m. The numerical simulation shows that when the working face advances to 80 m, the caving-zone height is approximately 14 m and the fractured-zone height is approximately 55 m. The theoretical and numerical results are in good agreement, indicating that the proposed model can effectively capture the development law of the overburden three-zone structure in the goaf of a Y-type ventilation working face.
Effect of Operating Parameters on Rock-Breaking and Hole-Forming Characteristics of High-Pressure Abrasive Water Jet
High-pressure abrasive water jet (AWJ) technology offers a promising alternative to traditional mechanical drilling in coal and geotechnical engineering. This study investigates the rock-breaking and hole-forming characteristics of AWJs on typical sandstone (70 MPa) using a custom-built experimental system. Single-factor experiments were conducted to evaluate the effects of abrasive particle size, jet pressure, and standoff distance. Results indicate that hole depth and diameter peak at an optimal abrasive size of 60 mesh. Increasing jet pressure (20–50 MPa) significantly enhances both penetration depth and hole diameter. Conversely, increasing the standoff distance (30–60 mm) enlarges the hole diameter but reduces the penetration depth. These findings provide a reliable basis for optimizing AWJ drilling parameters in engineering applications.