Search Results (138)

To address the issues of low permeability, clogging susceptibility, and insufficient circumferential bearing capacity of traditional drainage blind pipes behind tunnel linings in water-rich areas, this study proposes a novel curved-mesh circumferential drainage blind pipe specifically designed for such environments. First, through engineering surveys and comparative analysis, the limitations and application demands of conventional circumferential annular drainage blind pipes in highway tunnels were identified. Based on this, the key parameters of the new blind pipe—including material, wall thickness, and aperture size—were determined. Laboratory tests were then conducted to evaluate the performance of the newly developed pipe. Subsequently, the pipe was applied in a real-world tunnel project, where a construction process and an in-service blockage inspection method for circumferential drainage pipes were proposed. Field application results indicate that, compared to commonly used FH50 soft permeable pipes and F100 semi-split spring pipes, the novel curved-mesh drainage blind pipe exhibits superior circumferential load-bearing capacity, anti-clogging performance, and deformation resistance. The proposed structure provides a total permeable area exceeding 17,500 mm², three to four times larger than that of conventional drainage pipes, effectively meeting the drainage requirements behind tunnel linings in high-water-content zones. The use of four-way connectors enhanced integration with other drainage systems, and inspection of the internal conditions confirmed that the pipe remained free of clogging and deformation. Furthermore, the curved-mesh design offers better conformity with the primary support and demonstrates stronger adaptability to complex installation conditions. Full article

This study investigates measurement methods for and the distribution characteristics of normal stress within tire–road contact areas. A novel measurement method, integrating 3D scanning technology with bearing area curve (BAC) analysis, is proposed. This method quantifies the rubber penetration depth and calculates contact stress based on rubber deformation. The key innovation of this method lies in this integrated methodology for high-precision stress mapping. In the spatial domain, stress distribution is characterized by the percentage of area occupied by different stress intervals, while in the frequency domain, stress levels are analyzed at various frequencies. The results demonstrate that as the Mean Profile Depth (MPD) of the road texture increases, the areas under stress greater than 1.0 MPa increase, while the areas under stress less than 0.8 MPa decrease. However, when the MPD exceeds 0.7 mm, this effect becomes less pronounced. Higher loads and harder rubber reduce the proportion of areas under lower stress and increase the proportion under higher stress. Low-frequency (<800 1/m) stress components increase with an MPD up to 0.7 mm, beyond which they exhibit diminished sensitivity. Stress at the same frequency is not significantly affected by load variation but increases markedly with increasing rubber hardness. This research provides crucial insights into contact stress distribution, establishing a foundation for analyzing road friction and optimizing surface texture design oriented towards high-friction pavements. Full article

In this study, landslide risk assessment was conducted in the Renhe District, Panzhihua City, China. Firstly, based on 190 landslide points and 10 influencing factors, the landslide hazard was assessed using three models: random forest (RF), eXtreme Gradient Boosting (XGBoost), and Tabular Prior-data Fitted Network (TabPFN). The results indicate that the RF and XGBoost models exhibit comparable performance, both demonstrating strong generalization and accuracy, with the RF model achieving superior generalization, as evidenced by an area-under-the-curve (AUC) value of 0.9471. While the AUC value of TabPFN is 0.9243, indicating higher accuracy, it also poses a risk of overfitting and is therefore more suitable for applications involving small sample sizes and the need for rapid responses. The vulnerability assessment utilized the Analytic Hierarchy Process (AHP) to determine the weights of four disaster-bearing bodies, with sensitivity analysis revealing that road type was the most sensitive vulnerability factor. Finally, the landslide risk-assessment map of the Renhe District was produced by integrating the landslide hazard assessment map with the vulnerability assessment map. The findings indicate that the high-risk zones comprised 2.08% of the research region, which includes three principal train stations and necessitates enhanced protective measures. The medium-risk zones comprise 34.23% of the total area and are scattered throughout the region. It is important to enhance local capabilities for landslide monitoring and early warning systems. Relevant conclusions can provide a significant reference for landslide disaster prevention and mitigation work in the Renhe District and help ensure the safe operation of public transport infrastructure, such as railway stations and airports in the district. Full article

This paper presents an experimental and numerical investigation of the axial compression behavior of perforated cold-formed steel upright profiles commonly used in pallet racking systems. The primary objective is to examine how slenderness influences the failure modes and load-bearing capacity of these structural elements. Three column lengths, representative of typical vertical spacing in industrial rack systems, were tested under pin-ended boundary conditions. All specimens were fabricated from 2 mm thick S355 steel sheets, incorporating web perforations and a central longitudinal stiffener. Experimental results highlighted three distinct failure mechanisms dependent on slenderness: local buckling for short columns (SS-340), combined distortional–flexural buckling for medium-length columns (MS-990), and global flexural buckling for slender columns (TS-1990). Finite Element Method (FEM) models developed using ANSYS Workbench 2021 R1 software accurately replicated the observed deformation patterns, stress concentrations, and load–displacement curves, with numerical results differing by less than 5% from experimental peak loads. Analytical evaluations performed using the Effective Width Method (EWM) and Direct Strength Method (DSM), following EN 1993-1-3 and AISI S100 specifications, indicated that EWM tends to underestimate the ultimate strength by up to 15%, whereas DSM provided results within 2–7% of experimental values, especially when the entire net cross-sectional area was considered fully effective. The originality of the study is the comprehensive evaluation of full-scale, perforated, stiffened cold-formed steel uprights, supported by robust experimental validation and detailed comparative analyses between FEM, EWM, and DSM methodologies. Findings demonstrate that DSM can be reliably applied to perforated sections with moderate slenderness and adequate web stiffening, without requiring further local reduction in the net cross-sectional area. Full article

Anxiety and stress-related disorders affect all ages in all geographical areas. As high anxiety and chronic stress result in the modulation of mitochondrial pathways, intensive research is being carried out on pharmaceutical interventions that alleviate pertinent symptomatology. Therefore, innovative approaches being currently pursued include substances that target mitochondria bearing an antioxidant moiety. In this study, a newly synthesized antioxidant consisting of triphenylphosphine (TPP), a six-carbon alkyl spacer, and hydroxytyrosol (HT) was administered orally to mice via drinking water. Cerebellum and liver samples were collected and analyzed using ultra-high-performance liquid chromatography-tandem triple quadrupole mass spectrometry (UHPLC-MS/MS) to assess the levels of TPP-HT in the respective tissues to evaluate in vivo administration efficacy. Sample preparation included extraction with appropriate solvents and a preconcentration step to achieve the required sensitivity. Both methods were validated in terms of selectivity, linearity, accuracy, and limits of detection and quantification. Additionally, a workflow for evaluating and statistically summarizing multiple fortified calibration curves was devised. TPP-HT penetrates the blood–brain barrier (BBB), with a level of 11.5 ng g⁻¹ quantified in the cerebellum, whereas a level of 4.8 ng g⁻¹ was detected in the liver, highlighting the plausibility of orally administering TPP-HT to achieve mitochondrial targeting. Full article

This study investigates the impact of the bearing plate position on the uplift bearing capacity of low-header concrete expanded pile (CEP) foundations using the ANSYS finite element simulation method. Nine models of low-header CEP single piles with varying bearing plate positions are constructed. Incremental loading is applied to obtain relevant data, including load–displacement curves for vertical tensile forces, displacement contours, and shear stress distributions. The study analyzes the characteristics of load–displacement curves under different loading conditions, the axial force distribution along the pile shaft, the failure state of the surrounding soil, and how the uplift bearing capacity varies with changes in the bearing plate position. Based on the findings, a calculation model for the uplift bearing capacity of low-header CEP single-pile foundations is proposed. Given that the uplift bearing capacity decreases to varying degrees depending on the bearing plate position, the slip-line theory from previous studies is applied to refine the corresponding calculation formula for uplift bearing capacity. The results from the ANSYS finite element simulation confirm that the bearing plate position significantly influences the uplift bearing performance of low-header CEP single-pile foundations. The uplift bearing capacity increases with the distance between the bearing plate and the low header, reaching a peak before decreasing beyond a certain threshold. Considering the influence of the bearing plate position on bearing capacity, the affected area of soil beneath the foundation, and the time required for the system to enter its working state, the optimal bearing plate position is found to be at a distance of d₁ = 4R₀ to 5R₀ from the top of the pile. Full article

Two types of reinforcing the half-tenon wood joints, one reinforced with an energy dissipation plate (SW-1) and the other by a steel sleeve with energy dissipation plate (SW-2), were designed. The pure wood beam–column joint specimen SW-0, specimen SW-1 and specimen SW-2 were experimented by the monotonic loading test, and the corresponding failure mode of joints and load–displacement curve were obtained. Based on the reliability of the verified finite element numerical model, the impact of thickness of the energy dissipation plate on the seismic performance of the SW-2 joint was analyzed. The research results show that the SW-0 and SW-1 joints exhibited significant tenon pulling phenomena, while the SW-2 joint did not show this phenomenon. The initial stiffness of the joints is significantly improved after reinforcement, and the initial stiffness of the SW-1 and SW-2 specimens is 2.64 and 7.24 times that of the SW-0 specimen, respectively. The ultimate loads of specimens SW-0, SW-1 and SW-2 are, respectively, 2.8 kN, 6.2 kN and 24.9 kN. The enclosed area of hysteresis loop and the slope of skeleton curve gradually increase as the thickness of the energy dissipation plate increases, resulting in a significant enhancement in energy dissipation capacity. The ultimate bearing capacity of the joint and the slope of skeleton curve exhibit negligible variation when the thickness of energy dissipation plate exceeds 2.0 mm, and the corresponding optimal thickness is obtained as 2 mm. Full article

In developing countries with high seismic activity, a need exists to construct resilient infrastructure and reduce the housing deficit. Industrialized timber construction and the implementation of seismic isolation interfaces may represent a good alternative to respond to these demands. This paper studies the feasibility of constructing cross-laminated timber (CLT) buildings equipped with frictional pendulum bearings in Chile or similar highly seismic regions. The first part of this study shows a first-order approach for modeling the highly nonlinear behavior of CLT walls using a Smooth Hysteretic Model (SHM). An equivalent model of a base-isolated building was developed using the SHM as well as a physical model of the Friction Pendulum System in order to assess the seismic performance of CLT buildings with frictional isolators. The second part of this research presents and discusses the results of a broad parametric analysis concerning the seismic performance of base-isolated CLT buildings. The seismic assessment was carried out by deriving fragility curves and including the uncertainty linked to the seismic input and the friction coefficient of the isolation system. Constructing lateral resistant systems based on CLT walls presents a feasible alternative for buildings in high seismic hazard areas. Excellent seismic performance is achieved if the superstructure’s is designed with a reduction factor of 1, or if the superstructure’s fundamental period ranges from 0.6 to 0.9 s and is designed with a reduction factor of 2 and ductility capacity of 6 or more. An excellent seismic performance can be obtained for larger reduction factor values if the superstructure has middle to high maximum ductility capacity. Full article

In many construction applications, including bridge pedestals, concrete corbels, and concrete anchors, the concrete’s local compressive strength attribute (bearing) is crucial. One of the benefits from concrete’s bearing is its role in mitigation construction failure risk and increase the safety of the buildings. The local compression characteristics of fully hardened concrete were the primary focus of earlier study, with less attention paid to early age concrete (less than 28 days). In order to evaluate the bearing qualities of early age concrete—here defined as the first month—the current experimental program is being carried out. While the bearing plate’s area (Ab), which was placed in the middle of each block’s top surface, differed in dimension (100 × 100 mm, 80 × 80 mm, 60 × 60 mm, and 40 × 40 mm), the concrete pedestals’ size remained constant at 250 × 250 × 200 mm. Tests were conducted on sixteen concrete supports. Four equal groups of samples were created, and each group underwent testing at a different age (T = 3, 7, 15, and 28 days). In each group, unloaded-to-loaded area is varied (A₁/A_b = 6.25, 9.76, 17.36, and 39). The failure, bearing stress–slip curve, ultimate bearing strength and ultimate associated deformation of the tested concrete supports were studied. The results showed that the compressive and tension strengths increased by 178% and 244% when the concrete age reached 28 days compared to 3 days-concrete. As A₁/A_b or/and concrete age increased, the bearing characteristics improved more. The ultimate bearing strength increased by 51%, 56.5%, and 69.5% at $\sqrt{{\displaystyle \frac{A_1}{A_b}}}$ = 6.25 when the samples’ concrete age increased from 3 to 7, 15, and 28 days. The main contribution of this study is a novel formula to forecast the concrete’s bearing strength while accounting for the impact of the concrete’s age and the ratio $\sqrt{{\displaystyle \frac{A_1}{A_b}}}$. Full article

In response to the difficulty of controlling the layered composite roof of large-section coal roadways and the problem of slow excavation speed caused by unreasonable support parameter values, a dynamic staged control principle for surrounding rock based on “high-strength passive temporary support near the excavation face, combined with active support of rear bolts and anchor cables” is proposed by analyzing the evolution law of rock release stress under the spatial effect of excavation face. Based on the geological conditions of the 1211 (1) transportation roadway in Guqiao Coal Mine, a similar physical simulation test model was constructed to conduct experimental research on the bearing capacity and deformation instability mechanism of the surrounding rock of the layered-composite-roof coal roadway. The law of influence of staged support on the deformation and failure evolution of the surrounding rock was obtained. The research results show the following: (1) After loading above the model, the vertical stress on the roof increases rapidly in a “stepped” manner. After unloading the roadway excavation, due to the release of constraints on the roof above the roadway, the vertical stress on the roof rapidly decreases, especially in the temporary support area where the reduction in vertical stress on the roof is most significant. (2) As the vertical load increases, the displacement curve of the roof gradually evolves into a “V” shape. The farther away from the center of the roadway, the smaller the subsidence of the roof. When loaded to 54.45 kN, the subsidence of the roof increases, indicating that the development of roof delamination cracks is faster, and delamination occurs between 12 cm and 22 cm above the roof. (3) With the continuous increase of axial load, cracks first appear around the roof and slightly sink. Then, the cracks gradually expand and penetrate, causing instability and failure of the roadway roof. When the mining stress reaches 54.45 kN, the middle part of the roadway roof in the axial direction breaks, and the cracks penetrate, resulting in overall collapse. Full article

The seismic performance of an electric power system is crucial for maintaining the functionality of urban communities following an earthquake. In thermal power plants, the RC frame–shear wall structure plays a key role in providing seismic resistance to the main building’s longitudinal structural system. This study presents the results of a series of pseudo-dynamic tests on a two-span, four-story frame–shear wall model with a scale of 1/8. The prototype structure was a seven-story, seven-bay longitudinal RC frame–shear wall from the main workshop of a large thermal power plant. The cracking process, yielding sequence, hysteresis curves, and skeleton curve were obtained. Based on the test results, the energy dissipation, equivalent viscous damping coefficient, ductility and deformation, stiffness degradation, dynamic response, and displacement response were analyzed. The results showed that the RC frame–shear wall structure exhibits a high energy dissipation capacity and excellent seismic performance, and the shear wall significantly influences the structural bearing capacity and deformation performance. These findings offer valuable guidance for the seismic design of RC frame–shear wall structures in high-rise and large factory buildings. As the shear wall absorbs the majority of seismic forces and minimizes the concentration of plastic deformation, strengthening critical weak areas—such as increasing the horizontal distribution of rebars or improving the concrete strength at the shear wall base—can enhance overall structural performance and seismic resilience in industrial buildings subject to seismic loading. Full article

Due to Paleo-clay’s unique properties and widespread distribution throughout China, it is essential in geotechnical engineering. Rainfall frequently causes the deformation of Paleo-clay slopes, making slope instability prediction crucial for disaster prevention. This study explored Paleo-clay’s strength degradation and slope stability under soaking and wet–dry cycles. Using Mohr–Coulomb failure envelopes from experiments, curve fitting was used to find the patterns of Paleo-clay strength degradation. Finite element simulations and the strength discounting method were used to analyze the stability and deformation of Paleo-clay slopes. The results indicate that wet–dry cycles impact them more than soaking. Paleo-clay’s cohesion decreases exponentially as the number of wet–dry cycles and soaking times rise, but the internal friction angle changes very little. After 10 wet–dry cycles and 24 days of soaking, iron-bearing clay’s cohesion decreased to 17% and 44% and reticular clay’s to 32% and 48%. Based on the study area characteristics, three slope types were constructed. Their stability exhibited exponential decay. Under soaking, stability remained above 1.4; under wet–dry cycles, type I and II stability fell below 1.0, leading to deformation and failure. All types showed traction landslides with sliding zones transitioning from deep to shallow. Practical engineering should focus on the shallow failures of Paleo-clay slopes. Full article

Steel traditional Chinese buildings (STCBs) are constructed using modern materials, replicating the esthetics of ancient Chinese buildings, but their irregular joints differ significantly from those in conventional steel structures. To investigate the influence of beam section shape and axial compression ratio on the failure mode and shear resistance of all-welded irregular joints (WIJs) in STCBs, the size proportion relationships in the traditional Chinese modular construction system for such joints in existing practical projects are analyzed. Four exterior joint specimens were designed and fabricated for pseudo-static loading tests. The failure mode, hysteresis curve, and skeleton curve of the specimens were obtained. The test results indicate that the failure mode of the specimens involves shear deformation in the lower core area, with final failure due to crack formation in the weld at the junction between the column wall and the beam flange. As the axial compression ratio increases, the bearing capacity of the joint decreases. Based on the test results, the numerical model was established by using finite element software Abaqus2016, and parameter analysis was performed by varying the axial compression ratio of the column. After analyzing the force transfer mechanism of the core area in the WIJs of STCBs, a simplified calculation formula for the shear bearing capacity of the core area was derived based on the proportional relationship outlined in the construction manual from the Song Dynasty. The calculated results show good agreement with the experimental results, providing a basis for the structural design of WIJs in STCBs. Full article

This study investigates the design and mechanical evaluation of hydroxyapatite (HAp) scaffolds for bone tissue engineering, using stereolithography (SLA) to fabricate homogeneous and hollow elongated Voronoi structures. HAp, known for its biocompatibility and biodegradability, was selected to create scaffolds with a structure that supports cell growth. Both scaffold designs were tested under compression to measure key properties, including compressive strength, Young’s modulus, stiffness, and energy absorption. The homogeneous design demonstrated superior mechanical properties, achieving a maximum load of 913.6 N at a displacement of 0.166 mm and a stiffness of 5162.8 N/mm, indicating a higher load-bearing capacity and energy absorption compared to the hollow design. Despite these strengths, failure analysis revealed early fractures at strut junctions, particularly in slender areas, leading to fluctuations in the load–displacement curve and suggesting a risk to neighboring tissues in practical applications. These findings underscore the potential of Voronoi-based scaffolds for orthopedic use, while also highlighting the need for structural refinements to improve scaffold durability and clinical effectiveness. Full article

The Xiong’ershan district is situated on the southern margin of the North China Craton (NCC) and located within the Qinling–Dabieshan Orogen’s orogenic zone. It is adjacent to the XiaoQinling mining district and exhibits very favorable geological conditions for mineralization, as the district contains numerous gold deposits, positioning it as one of the key gold-producing areas of China. The Miaoling gold deposit is a hydrothermal deposit and is controlled by the Mesozoic nearly NS-trending fault. The ore bodies are hosted in the Mesoproterozoic Xiong’er Group of the Changcheng System of volcanic rocks, with reserves reaching large-scale levels. Pyrite is the main gold-bearing mineral and can be classified into four generations: early-stage fine- to medium-grained euhedral to subhedral cubic pyrite (Py1); medium- to coarse-grained euhedral to subhedral cubic granular pyrite in quartz veins (Py2a); fine-grained subhedral to anhedral disseminated pyrite in altered rocks (Py2b); and late-stage anhedral granular and fine-veinlet pyrite in later quartz veins (Py3). Through in situ trace element analysis of the pyrite using LA-ICP-MS, a positive correlation between Au and As was observed during the main mineralization stage; gold mainly exists as a solid solution within the pyrite lattice, and the ablation signal curve reflecting the intensity of trace element signals showed that gold also occurs as micron-scale mineral inclusions. The trace element content suggested a gradual increase in oxygen fugacity from Stage 1 to Stage 2, followed by a decrease from Stage 2 to Stage 3. The Co/Ni values in the pyrite (0.56 to 62.02, with an average of 12.34) exhibited characteristics of magmatic hydrothermal pyrite. The in situ sulfur isotope analysis of the pyrite using LA-MC-ICP-MS showed δ³⁴S values of 4.24‰ for Stage 1, −6.63‰ to −13.79‰ for Stage 2, and −4.31‰ to −5.15‰ for Stage 3. Considering sulfur isotope fractionation, the δ³⁴S value of the hydrothermal fluid during the main mineralization stage was calculated to be between 0.31‰ and 2.68‰. Full article