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Neck pain and low back pain are major challenges in public health, and intervertebral disc (IVD) biomechanics is an important multidisciplinary field. To date, no bibliometric literature review of the relevant literature has been performed, so we explored the emerging trends, landmark studies, and major contributors to IVD biomechanics research. We searched the Web of Science core collection (1900– 2022) using keywords mainly composed of "biomechanics" and "intervertebral disc" to conduct a bibliometric analysis of original papers and their references, focusing on citations, authors, journals, and countries/regions. A co-citation analysis and clustering of the references were also completed. A total of 3189 records met the inclusion criteria. In the co-citation network, cluster #0, labeled as "annulus fibrosus tissue engineering", and cluster #1, labeled as "micromechanical environment", were the biggest clusters. References by MacLean et al and Holzapfel et al were positioned exactly between them and had high betweenness centrality. There existed a research topic evolution between mechanobiology and mechanical repair strategies of IVDs, and the latter had been identified as an emerging trend in IVD biomechanics. Numerous landmark studies had contributed to several fields, including mechanical testing of normal and pathological IVDs, mechanical evaluation of new repair strategies and development of finite element model. Adams MA was the author most cited by IVD biomechanics papers. Spine, the European Spine Journal, and the Journal of Biomechanics were the three journals where the most original articles and their references have been published. The United States has contributed most to the literature (n = 1277 papers); however, the research output of China is increasing. In conclusion, the present study suggests that IVD repair is an emerging trend in IVD biomechanics. [ABSTRACT FROM AUTHOR]

In recent years, with the completion of the construction of large-scale hydropower projects in China, a series of engineering geological problems that occurred during the operation of the hydropower station have become an important issue affecting the normal operation of hydropower stations. Landslides on reservoir slopes triggered especially by water storage and other factors related to the construction of hydropower stations seriously affect the normal operation of the hydropower station and lead to other geological disasters. Research indicates that many reservoir-area landslides are triggered by hydrodynamic forces resulting from water level fluctuations in hydroelectric power stations. The Mala landslide of Miaowei Hydropower Station in the Lancang River Basin of China is taken as the engineering example to study the influence of hydrodynamic forces on the deformation characteristics and stability trends of the landslide. This paper explores the formation mechanism and influencing factors of the Mala landslide by conducting a field investigation of the Mala landslide and analyzing the monitoring data. Additionally, this paper also discusses the impacts of water storage, rainfall, and engineering construction on landslide induction. It is considered that the evolution of the Mala landslide from the initial stage of water storage to the current state mainly includes four stages: small-scale bank collapse stage, creep deformation stage, accelerated sliding stage, and uniform sliding stage. Moreover, the changes in the trend of landslide stability are analyzed using the two-dimensional finite element method. The research results provide a valuable reference for understanding the formation mechanism and predicting the deformation of reservoir landslides, which has considerable engineering practical significance. [ABSTRACT FROM AUTHOR]

Sanding production of the underground gas storage (UGS) in the depleted reservoir will cause the decline of effective storage capacity, and the erosion of well string and auxiliary equipment, and other engineering problems. A deep understanding of the sanding production contributes to maintaining the injection and production capacity of gas storage and the long‐term safety of the UGS. In this paper, core samples of five main sedimentary microfacies were drilled from the UGS in middle China. The mechanical properties with different conditions of the moisture content in multi‐cycling injection–production process were tested. The critical drawdown pressure (CDP) calculation methods for the UGS were established based on the stress analysis near the wellbore and the Mogi–Coulomb criterion. Adopting the finite element method simulation on the geological model of the target UGS, the geo‐stress of the formation was calculated by inversed analysis and validated based on the Kaiser effect of rock. Then, the CDP of two target wells of the UGS were investigated. The effects of the water moisture and the cycling times of the injection–production process on the CDP were also analyzed. The geo‐stress distribution shows that the horizontal maximum principal stress ranges from 53 to 68 MPa, and the horizontal minimum principal stress is 46–58 MPa in the target reservoir section, and the vertical minimum principal stress is 69–77 MPa in the target reservoir. The calculated CDP changed with the types of the sedimentary microfacies in the range of [6.27, 8.77] MPa, in which the CDP of the mixed mud and sand flat sedimentary facies was the lowest. The weakness of the CDP with the increasing of the moisture content and the cycling times were analyzed quantitively. [ABSTRACT FROM AUTHOR]

Architectural heritage health assessment is the basis of scientific repair and maintenance. However, existing methods do not adequately take into account the fuzziness, randomness and uncertainties unique to architectural heritage assessment. In this paper, a new evaluation model of VM-NCM is constructed by combining variable weight theory and normal cloud model theory. The model enables the combination of qualitative ratings and quantitative calculation, deals with the fuzziness in the assessment process, and resolves the randomness and reflects the uncertainty to a certain extent. Based on constructing the index system combining qualitative and quantitative indexes, the structural index values are acquired by the synergistic coupling of the fine laser point cloud model and finite element structural analysis model. The acquisition of surface index values is completed by the hyperspectral intelligent detection technology of surface materials and diseases. These reduce the generation of ambiguous information in the index detection process. An evaluation study is conducted using the Yingxian wooden pagoda in China as an example. The results show that this method takes into account the fuzziness and randomness in the evaluation process, and obtains more scientific and reliable evaluation results, which provides a research paradigm for assessing the architectural heritage health status. [ABSTRACT FROM AUTHOR]

Based on the perspective of flight technology and flight safety, the unsaturated clayey foundation soil of a high plateau airport in the mountainous area of southwest China is taken as the research object, and the calculation method of the composite modulus of CFG pile composite foundation with the soil between the piles as the unsaturated soil is established according to the relevant characteristics of unsaturated soil, and the calculation method of the composite foundation's settlement is carried out on the basis of this method. At the same time, Plaxis finite element analysis software is used to model the actual project and numerically analyze the settlement characteristics of the composite foundation. Finally, the calculation results of the two methods are compared and studied with the actual settlement monitoring values on site. The study shows that: 1) the theoretical analysis method is able to consider the effects of pile length, pile modulus, and matrix suction in unsaturated soil of rigid piles on the composite modulus, which is more in line with the reality than the conventional composite modulus method that does not consider the unsaturated nature of the soil between the piles; 2) the resultant values computed by the theoretical and numerical analysis methods recommended in this paper are both smaller than those measured at the site but the difference is within the range of 10%, so that in the actual plateau of the High Plains airports can choose the two analysis methods recommended in this paper to conduct related research. [ABSTRACT FROM AUTHOR]

Accelerated bridge construction (ABC) has attracted much attention in China as a new and efficient construction method. However, the seismic performance of the connections between precast piers and other structures limits the application of ABC in medium and high seismic zones. In this paper, a quasi-static test was conducted to investigate the seismic performance differences between a cap–column socket connection (PSC) specimen, which reinforced an embedded RC column-to-precast cap beam with a socket connection, and a cast-in-place (CIP) cap–column specimen. A fiber-based finite element model that considers bond slippage between the connection reinforcement and wet joint concrete is proposed. The numerical simulation results compared with the experimental results show an error of about 12% in peak bearing capacity and about 2% in initial stiffness. The experimental and numerical results show that the PSC specimen demonstrates comparable seismic performance to the CIP specimen. Experimental results verified that the finite element model in this paper is adequate to predict the seismic responses of a precast column with a reinforcement-embedded socket connection. A reinforcement-embedded RC column-to-precast cap beam with socket connection can be an effective solution for construction in medium and high seismic areas. [ABSTRACT FROM AUTHOR]

With the popularized application of underground cable tunnels in China, various structural defects such as cracking, deforming and material deteriorating also emerge. In cable tunnels that have been poorly maintained for a long time, there is always a coexistence of several kinds of defects, and with the current methods of monitoring, it is difficult to identify the major defect affecting the load-carrying capacity and resolve it. However, the finite element method (FEM) can better solve this problem by analyzing the effect of a single defect parameter separately. In this paper, four different types of cable tunnels, namely the circular, rectangular, arched and trenched sectional tunnels, are modelled and analyzed with FEM. Defect parameters, including crack dimensions and concrete deterioration, are considered as variables, which are controlled and studied respectively. The results of the simulation indicate that the impact of crack propagation on the residual-bearing capacity of cable tunnels is much larger than that of concrete deterioration, especially the deepening of cracks. Works in this paper have the potential to be further referenced for cable-tunnel structure estimation and defect prevention. [ABSTRACT FROM AUTHOR]

Currently, in some domestic and foreign mines, the backfill drilling pipeline experiences a rupture phenomenon even when the wear degree is low. This results in a delay in production due to the filling becoming 'sick'. This paper presents, for the first time, the damage mechanism from a mechanical perspective and re-derives the anti-extrusion strength model of the backfill drilling pipeline. We investigate the influence of the law on the anti-extrusion strength of pipelines from the perspective of strata and cement rings. We then verify the theoretical and simulation results through engineering examples. The results demonstrate that the Mises stress criterion is a suitable modification principle for the anti-extrusion strength model of the backfill drilling pipeline. The anti-extrusion strength of the pipeline is related to the elastic modulus and Poisson's ratio of the stratum, and the thickness of the cement ring. It is negatively affected by the depth of the stratum. For hard strata, a cement ring with a smaller elastic modulus is suitable, while for soft stratum, a cement ring with a larger elastic modulus is recommended. When the missing angle of the cement ring is less than 60°, the stress concentration factor increases up to 2.2. The stress unloading capacity of the cement ring ranges from 32.7% to 37.8%, and optimal performance of the cement ring is achieved when it has high strength and low rigidity. The backfill filling pipeline of a copper mine abroad was destroyed due to external extrusion force exceeding its anti-extrusion strength value. The modified pipeline anti-extrusion strength model is 18.2% higher than the pipeline API strength value. This finding can inform the design of the backfill filling pipeline for China's kilometer-deep wells in the future. [ABSTRACT FROM AUTHOR]

The paper presents the results of computational analysis of the stress-strain state of reinforced concrete spans of the railway (single-track railway line) overpass over the highway, under specified loads using spatial finite element models. The static load consists of a cohesion of three TEM-18 diesel locomotives and two loaded gondola cars (up to 25 tons per axle). The purpose of this study was to ensure reliable and safe operation of artificial structures on the railroads, as there is a constant increase in transit freight trains from China through the territory of Kazakhstan to near and far abroad, and often the load on the axle reaches 25 tons, and sometimes larger values – up to 27 tons per axle. The results of the study are recommended to be used for inspections and tests of typical girder bridge spans, as well as in the case of monitoring their technical condition with increasing operational loads. [ABSTRACT FROM AUTHOR]

Aiming at the current low degree of mechanization of pomegranate sprouting tiller pruning in China, all relying on manual pruning, this paper designs a PLC-based pomegranate sprouting tiller removal machine. This machine adopts the identification method of wireless map transmission, the sprouting tiller removal method of multi-cylinder cooperative operation, and the MCGS configuration to realize the interaction between the user and the system, which realizes the displacement and angle compensation of the end-effector under complex conditions to realize the all-around accurate removal of the pomegranate sprouting tiller. The performance test and finite element analysis showed that the device could remove up to 74.62% of sprouting tillers, and the damage rate was as low as 18%. This meets the requirements of pomegranate plantations for the removal of emergent tillers. [ABSTRACT FROM AUTHOR]

Featured Application: This study is aimed at sensitivity of seismic fragility demand parameters caused by structural uncertainty of high-speed railway extradosed cable-stayed bridge considering the Yuanjiang extra-large bridge on Huaihua–Shangyang–Hengyang Railway in China. Based on the probability distribution and correlation of random parameters, a sampling analysis method is proposed herein. Furthermore, a dynamic 3D finite element model of the employed bridge is established by using OpenSEES nonlinear software with full consideration of the randomness of structural parameters using sampling analysis. Based on these findings, some important conclusions were drawn. We believe that our study makes a significant contribution to the literature because although existing studies have focused on static parameter sensitivity analyses and have provided evidence for the design and construction control of cable-stayed bridges, the dynamic sensitivity studies especially for the structural parameter uncertainty of high-speed railway extradosed cable-stayed bridges have not been extensively studied. Further, we believe that this paper will be of interest to the readership of your journal because our analysis employs innovative research techniques, and our findings have the potential to provide guidance for the seismic fragility analysis of high-speed railway extradosed cable-stayed bridges. This manuscript has not been published or presented elsewhere in part or in entirety and is not under consideration by another journal. We have read and understood your journal's policies, and we believe that neither the manuscript nor the study violates any of these. There are no conflicts of interest to declare. It is known that the extradosed cable-stayed bridge, a hybrid bridge, possesses the virtues of both classic cable-stayed bridges and girder bridges in mechanical behaviors. In this paper, the sensitivity of seismic fragility demand parameters (SFDP) of a high-speed railway extradosed cable-stayed bridge is studied systematically along with the consideration of structural parameter uncertainty. Based on the probability distribution and correlation of random parameters, the Latin hypercube sampling method is adopted herein. The dynamic 3D finite element model of the employed bridge is established by using powerful and attractive OpenSEES nonlinear software. A nonlinear incremental dynamic analysis is performed to consider the randomness of structural parameters using sampling analysis. Some important conclusions are drawn indicating that the structural design parameter uncertainty predominantly has influence on the SFDP for fragility analysis of bridge structures. The design parameters of extradosed cable-stayed bridges are categorized and identified as primary, secondary and insensitive parameters. The high sensitivity parameters of extradosed cable-stayed bridges for fragility analysis include friction coefficient of bearing, concrete bulk density, damping ratio, peak compressive strength of confined concrete, component size and peak strain of confined concrete. Additionally, the strength and strain of unconfined concrete cannot be ignored. Furthermore, the uncertainty of structural design parameters fails to be responsible for the cable force responses due to larger girder stiffness. The structural design parameter uncertainty has a significant influence on the responses of extradosed cable-stayed bridges for seismic fragility analysis. [ABSTRACT FROM AUTHOR]

Underwater wet-mateable connectors have been widely used to reduce the cost and the time of installation, maintenance and reconfiguration in many fields, such as the oil and gas (O&G) industry, offshore renewable energy (ORE), and undersea observatories. In the past few years, the authors' group has made some efforts in developing wet-mateable connectors. This paper presents a methodology for designing and testing a wet-mateable electrical connector. First, an innovative wet-mateable electrical connector with dual-bladder pressure-balanced oil-filled (PBOF) technology is proposed. Second, the generalized equations of differential pressure are derived. Then, a procedure of thermal-electric-structure (TES) coupling simulation is proposed, and a series of finite element analysis (FEA) involving coupled multi-field problems is conducted, including thermal-electric coupling analysis, static structural analysis, and dynamic analysis. Finally, a prototype of the proposed connector is developed successfully, and its electrical performance is verified by the online test in a hydrostatic pressure environment with an ocean depth of 3000 m, which has reached the leading level in China. This paper is the first discloser on wet-mateable connectors in the aspects of design, theory, simulation and testing, which might be helpful to many ocean scientists in developing countries who are technically blocked or could not afford the high cost. [ABSTRACT FROM AUTHOR]

The accumulation slope is widely distributed in the mountainous area of China; this paper takes the slope of the Chengdu–Lanzhou Railway as the engineering background and analyzes the stability of the slope and the mechanical properties of the anti-slip pile under symmetrical train loads. First, the finite element software Midas GTS NX was used to analyze the effect of the slope after the anti-slip pile support and the stability of the slope at different pile spacings, pile row distances, and pile positions. Then, the finite element analysis results of the pile-side earth pressure and landslide thrust were compared with those of earth pressure theory, the standard method, and field-measured data. The results of this paper are as follows: (1) The anti-slip pile support increased the slope stability coefficient from 1.175 to 1.680. (2) The slope stability gradually decreased with increases in anti-slip pile spacing and pile row distance and rose first and then decreased with an increase in pile position. (3) The active earth pressure values behind the pile by Coulomb theory were slightly smaller than the finite element analysis result; the theoretical values of the passive pressure before the pile were much larger than the finite element analysis results. (4) The landslide thrust was calculated by the transfer coefficient method when the safety factor K = 1.00. The results of explicit method and implicit method were the same, which were 8–19% higher than the finite element simulation value; when the safety factor K = 1.35, the theoretical value of the explicit method was about three times the simulated value, and the theoretical value of the implicit method was about 2.3 times the simulated value. (5) The measured values verified that the simulated values had a certain degree of reliability, and the relative deviation between the two was 5–17%. [ABSTRACT FROM AUTHOR]

Super-large span twin tunnels, which can relieve traffic burden and improve the efficiency of roads, have been rapidly popularized in urban construction. Hence, it is very important to master the share rate of support structure in this sort of tunnel correctly. In this paper, some field monitoring and numerical simulation work has been carried out in such a tunnel in Daling, China. The content of field monitoring consisted of the vault settlement, stress of the concrete, and the sum pressure. Firstly, the calculation formula of rock pressure in this kind of tunnel had been deduced, which was based on the theoretical sliding failure mode. Then, the calculated rock pressure was applied to the load structure model step by step with 10% intervals (10%, 20%, ...). By comparing the monitoring and the simulation results on vault settlement, the share rate of the primary support was ensured to be 40%. Similarly, by comparing the result on safety factors, the share rate of the secondary lining was obtained (40%). The remained load was born mainly by the surrounding rock itself and the advanced support. Finally, the reliability of the results were verified by the sum pressure. This paper can provide reference for the effective design of support structure in super-large span twin tunnels. [ABSTRACT FROM AUTHOR]

This paper examines the dynamic performance of the pantograph passing through an overlap section of the catenary system, using a China's high speed railway with the 4-span overlap as an example. The pantograph and catenary system are simulated as a lumped mass model and finite element model, respectively. The model is verified according to EN50318:2018. The model is also assessed against an experimental study of the contact force and uplift of contact wire at 300 km/h. Then the contact force and uplift of contact wire at the speed of 150–350 km/h are calculated. The research shows that when the pantograph passes through the overlap, the maximum contact force increases beyond 14%, the standard deviation of the contact force increases by more than 26%, and the increase of the vertical displacement exceeds 38%, which becomes more apparent with the increase of speed. Under the influence of aerodynamic force, when the running speed increases from 150 to 350 km/h, the mean contact force in the knuckle-downstream and knuckle-upstream orientation increase by 59.49% and 97.85%, respectively. As a result, the contact force and vertical displacement increase greatly when passing through the overlap section, which could affect the current collection quality. [ABSTRACT FROM AUTHOR]

Traditionally, temperature control for massive concrete structures during the construction phase is based on experience instead of using advanced methods such as predictive control method. In this paper, a predictive control method with a hybrid data-based artificial neural network (ANN) model is proposed. The main parameters of the numerical model are identified based on the data measured from the site. Since the limitation of the measured data, a rich dataset is generated by the numerical model with the identified parameters. Finally, a hybrid data-based ANN model for predicting the temperature indicator of massive concrete is developed. A case study in which the temperature control of concrete in a real bridge anchorage foundation construction in Southwestern China is conducted. Results show that the maximum temperature of concrete can be controlled around the target temperature by the proposed method. The average temperature decline rate decreases from 0.19 °C/h to 0.14 °C/h in the period of 120 h (i.e., from 60 h to 180 h after the concrete pouring) at a sudden decrease of 8 °C in environmental temperature, thereby enabling a significant reduction in the risk of concrete cracking. [ABSTRACT FROM AUTHOR]

In seismically active regions, high-filled embankment slopes on liquefiable soils tend to damage after strong earthquakes. Therefore, post-seismic damages should be estimated as soon as possible to mitigate potential losses. Fragility function is an efficient tool for assessing the seismic vulnerability conditions of structures, which links the probability of exceeding different limit states to seismic intensity. An embankment slope on liquefiable soils at Yading Airport in China was selected as the study object, and a series of numerical analyses of the embankment-foundation system utilizing the finite element method were conducted. Advanced dynamic constitutive models considering liquefaction and hysteresis characteristics were also adopted to simulate the nonlinear stress–strain behavior of soils under cyclic loadings. The post-seismic stability of embankment slopes was assessed using the strength reduction method (SRM) based on the stress–strain analysis. On this basis, the permanent ground deformation (PGD) at the ground-free field conditions was selected as the intensity measure (IM), while the factor of safety (FoS) of the slopes was selected as the damage measure (DM). Then, a procedure was presented for deriving seismic fragility functions with different damage states in light of incremental dynamic analysis (IDA). This paper aims to investigate the effects of different embankment typologies, such as the thickness of liquefiable soils and slope inclination, on the post-seismic vulnerability of embankment slopes. The fragility curves constructed in this study may soon be helpful for predicting the post-seismic damage of similar high-filled embankment slopes on liquefiable soils, which enables efficient traffic control and rapid disaster response. [ABSTRACT FROM AUTHOR]

To effectively identify the key material parameters of different zones of concrete face rockfill dams and improve the efficiency of parameter optimization, a global sensitivity analysis method of parameters based on sparse polynomial chaotic expansion (sPCE) is proposed in this paper. The latin hypercube sampling method is used to select multiple groups of material parameters, and then finite element method is used to calculate the displacement of dam characteristic nodes in dam body. On this basis, the displacement is expanded by sPCE, and the polynomial basis function is reconstructed by orthogonal matching pursuit to improve the construction and analysis efficiency of the proxy model. According to the chaos coefficients, Sobol' indices are calculated to evaluate the influence of the material parameters and their interaction on different displacements of the dam. The results show that the sPCE model can accurately simulate dam displacement and its statistical characteristics with a relatively small sample size. The sensitivity of the same parameter has spatial variability, and under the influence of parameter levels and spatial distribution of different materials, the parameter sensitivity ranking of different zones has certain differences. The proposed method provides a new reference to sensitivity analysis and uncertainty analysis for practical engineering. [ABSTRACT FROM AUTHOR]

Vibration analysis of bridges induced by train loads is a crucial aspect of railway design, particularly considering the complexity of vehicle components such as bogie-suspension systems. Consequently, railway engineers have endeavored to improve the computational efficiency and applicability of train models using the finite-element method. This paper introduces a toolbox implemented in ABAQUS through a user-defined element (UEL) subroutine, which incorporates the vehicle–bridge interaction (VBI) element theory. This toolbox effectively handles diverse vehicle–bridge interaction systems. In the proposed theory, the wheel-track contact force is derived based on the bridge response, eliminating the need for an iterative process and significantly reducing computational workload compared to classical physics-based analysis. The presented approach is validated through a moving sprung mass model and a moving rigid bar model. Furthermore, a case study is conducted on a three-dimensional finite-element model of a high-speed railway bridge in China, based on a design sketch, to showcase the capabilities of the developed scheme. The study demonstrates the practical application of the proposed methodology in analyzing vehicle–bridge structures with high complexity. [ABSTRACT FROM AUTHOR]

There have been several cases of large cooling towers being damaged by wind in history. A typhoon has the characteristics of a strong wind field energy and large shear wind speed. This paper simulates the entire collapse process of large hyperbolic cooling towers by the action of typhoons and refines the typhoon-induced failure mechanism for cooling towers. Firstly, based on WRF-CFD wind field downscaling technology, a fine simulation of the near-ground multiscale wind field produced by China's strongest typhoon "Typhoon Rammasun" is performed to extract effective three-dimensional (3D) typhoon load input parameters. Then, by loading the obtained 3D wind load on the finite element model, a pseudo-dynamic analysis of the world's tallest cooling tower "Luan Cooling Tower" is performed based on LS-DYNA explicit dynamic analysis, and the typhoon-induced collapse process is simulated. Finally, the stress distribution and distortions of the tower and the response time history of key units are compared and analyzed to determine the collapse mechanism. The process of collapse begins with large deformation of the windward surface of the tower throat, which shows folds in the range of 62° on both sides. Eventually, collapse occurs due to uncoordinated deformation. The collapse mechanism can be divided into a bending arch mechanism and a suspension wire mechanism. [ABSTRACT FROM AUTHOR]

Reinforced concrete (RC) rigid-frame bridges with tall hollow piers were widely constructed in Southwestern China, an earthquake-prone area. For such bridges, the seismic damages may be underestimated if multiple bends of tall piers are overlooked using a conventional damage measure such as the drift ratio. Moreover, the seismic damage assessment can be inaccurate if tall piers' shear damages are ignored using the sectional curvature as a damage measure. Along these lines, this paper proposes a novel seismic damage measure, the piecewise drift ratio (PDR), involving both shear effects and multiple-bend deformations; it has been validated by hybrid tests and analyzed employing fragility curves. Damage state limits represented by the PDR are estimated through statistical analysis of the 40 existing tests of hollow piers. To validate the PDR, a finite element model of an RC rigid-frame bridge with two tall piers was established and adequately calibrated based on model-updating hybrid simulations. To comprehensively evaluate the PDR, ground motions were selected and grouped into four categories by identifying their first two-class nature frequency and their amplitude ratio; to determine fragility curves, both the spectral acceleration at the fundamental period with 5% damping, Sa(T1, 5%), and the peak ground acceleration have been adopted as intensity measures. Results show the effectiveness of the proposed PDR, provide a more severe ground motion for assessment, and reveal the high exceedance probability of the complete damage state of tall piers under some potential seismic scenarios. [ABSTRACT FROM AUTHOR]

As urban population increases, integrated underground–aboveground complexes are being constructed at growing paces in major cities. The seismic analysis of such complexes is crucial for the safety and functionality in the threat of potential earthquake disasters. However, fine‐grained numerical modeling and analysis of such large and complex structures are still inefficient due to the consideration of the soil–structure interaction (SSI). To address this challenge, an efficient approach for numerical modeling of large‐scale seismic SSI analysis is presented in this paper to overcome the limitations of existing finite element analysis (FEA) software. Moreover, a multi‐graphic processing unit (GPU) parallel explicit algorithm is implemented for the nonlinear dynamic SSI problems to further increase the computational efficiency. A large underground–aboveground complex project in China is used as an example to demonstrate the capability of the integrated method. The accuracy and reliability of the multi‐GPU parallel explicit finite element algorithm for SSI analysis (GFEA‐SSIA) are verified through a comparative analysis of the linear‐elastic and nonlinear dynamic response of the building calculated by GFEA‐SSIA and common FEA software. Finally, the structural response and structural damage of the underground–aboveground complex are analyzed under multidirectional seismic motions, and the damage distributions of the structures are provided. [ABSTRACT FROM AUTHOR]

Belled piles are increasingly being employed for transmission tower foundations in the mountainous regions of Western China, but their uplift behavior is not fully understood. This paper presents experimental investigations of the pull-out behavior of belled piles in horizontal and inclined ground (overlying soil and underlying soft rock). 3D non-linear finite element analyses related to the model tests were also conducted using ABAQUS software, and the influence of slope effect on the ultimate uplift capacity of rock-socketed belled piles was evaluated. The results demonstrated that the inclined ground led to deterioration in its uplift performance, thus increasing both the displacement of the pile cap and ground surface. When the slope angle changes between 0° and 30°, the weakening effect of the slope on the ultimate uplift capacity increases linearly. When the slope angle is increased to 45°, the weakening effect of the slope on the ultimate uplift capacity is greatly enhanced, and the relationship between the ultimate uplift capacity of belled piles in the inclined ground and the slope angle is proposed. Moreover, the failure mode of the horizontal bedrock is an inverted cone with a failure angle between 0.8 and 1.0φr (φr is the internal friction angle of bedrock). In contrast, the bedrock failure of inclined ground is bulb-shaped, and it mainly occurs within 4d (d represents pile diameter) of the downslope side. It was also discovered that the downslope side of the belled pile in the sloped ground generated cracks that directed to the pile axis if the pile top load reached 82.3% of the ultimate uplift capacity. These findings are valuable for practicing engineers in the rational design of belled piles, taking account of the weakening effect of inclined ground. Highlights: Reveal the adverse effect of inclined ground on the uplift bearing deformation characteristics of the belled pile. It is clarified that the failure mode of rock-socketed belled piles in inclined ground varies with the slope angle through model test and 3D numerical method. Propose an empirical relationship to quantify the ultimate uplift capacity of rock-socketed belled piles in inclined ground and the slope angle. [ABSTRACT FROM AUTHOR]

A Mw 6.6 earthquake struck Luding county, in Sichuan province of China on September 5, 2022, causing severe damage of nearby infrastructures. The earthquake indicates an awakening of southeast branch of Xianshuihe fault since the last 1973 Mw 7.6 Luhuo earthquake in Sichuan, thus attracting attention from the public. A physics-based method, combining spectral element method (SEM) and finite element method (FEM), was presented in this paper to investigate the correlation between near-fault motions and response of a road tunnel, which has a closest distance of about 6.0 km to the fault. This method allows to incorporate the rupture details, geological irregularity, 3D velocity structure, as well as the underground tunnel. The ground motions simulated by SEM were validated by comparison to specific station records and empirical ground motion model (GMM), which were subsequently input into the tunnel to obtain its axial deformation and sectional inner forces. Parametric study on tunnel alignment was conducted, and wavelet transformation was used to extract dynamic pulses from the ground motions. The results show that the tunnel response is remarkably affected by dynamic pulse directivity, and the axial forces could be dominated by permanent fault displacement for tunnel of the strike-normal alignment. [ABSTRACT FROM AUTHOR]

Analyzing the working conditions of a dam using safety monitoring indices (SMIs) is a relatively intuitive and effective method for dam safety evaluation. Therefore, a reasonable and accurate method for determining the SMIs of a dam is of vital importance for dam safety assessment. However, the current methods for determining the SMIs of dams, especially roller-compacted concrete (RCC) dams, have many shortcomings, such as ignoring the construction process of the dam, the coupling effect among multiple physical fields, etc. In this paper, a novel SMI determination method considering the seepage–stress coupling effects was proposed for RCC dams with the assistance of a constructed seepage and stress coupling model so as to address the deficiency of existing RCC dams in determining SMIs. The coupled mathematical model was developed in COMSOL Multiphysics to establish a finite element analysis model of an RCC gravity dam in Henan Province, China. Moreover, the seepage anisotropy of the RCC construction layers was also considered in the model. Finally, the seepage, stress, and deformation characteristics of the RCC dam were analyzed based on the model, and the seepage and deformation SMIs of the dam were determined and compared with traditional methods. The results show that seepage, stress, and displacement fields are distributed similarly for both coupled and uncoupled models. However, in contrast to the uncoupled model, the hydraulic head contour distribution is more dispersed in the coupled model. Additionally, the stress and displacement simulated by the coupled model increase at different rates, with a more pronounced stress concentration near the dam heel. Comparing the seepage and stress SMIs of RCC dam obtained from different methods, it was found that the indices of dam seepage discharge and crest displacement that are calculated by considering the seepage–stress coupling effect and anisotropic characteristics of RCC construction layers are 34.78% and 31.98% lower than results obtained by ignoring these two effects, respectively. Therefore, it is crucial to consider the seepage–stress coupling effect and the anisotropic characteristics of RCC when determining the SMIs for RCC dams. [ABSTRACT FROM AUTHOR]

According to the characteristics of marine natural gas hydrate, China has proposed the solid-state fluidization exploitation technology or natural gas hydrate, with subsea exploitation being key to the commercial recovery of gas. In this paper, two new integrated tools are proposed for breaking and collecting natural gas hydrate, and their working principles and steps are illustrated. Finite element analysis, three-dimensional modeling, and simulations were conducted for both exploitation tools to verify their technological feasibility. The results show that the two exploitation tools can effectively improve the efficiency of hydrate exploitation and ensure the stability of the hydrate reservoir. This provides a reference for further research on the solid-state fluidization exploitation technology of marine gas hydrates. [ABSTRACT FROM AUTHOR]

Research background: With the rapid development of civil engineering, the traditional low rise building model can no longer meet the needs of urbanization, and high-rise building structure has become the future development direction. In recent years, earthquake disasters occur frequently in China, which has caused huge losses to high-rise buildings. Therefore, we must strengthen the relevant research of high-rise building structures, which can make the high-rise building structural columns meet the requirements of safety performance. Therefore, the health detection and seismic performance evaluation of high-rise buildings will be of great significance. Research method: Through static elastic-plastic evaluation, we can calculate the dissipated strain energy of the structural column, which will further obtain the damage index of the structural column and obtain relevant data. Through this calculation method, we can complete the seismic performance evaluation of high-rise buildings, which is a calculation mode different from the traditional finite element software analysis. Through static elastic-plastic analysis, the seismic performance evaluation of high-rise buildings will have higher accuracy, which will build a damage index. Therefore, this paper uses a variety of research methods, mainly literature survey and empirical analysis. Through literature analysis, this paper can fully and correctly understand the methods of health detection and seismic performance evaluation of high-rise building structures at home and abroad, which will further clarify the current research level at home and abroad. Through empirical research, this paper analyzes specific examples, which can obtain more accurate results. Conclusion: In this paper, the seismic performance of high-rise buildings is comprehensively evaluated according to the damage index value of building structural columns. The simulation results show that more ideal seismic evaluation results can be obtained. [ABSTRACT FROM AUTHOR]

The assembled hollow-core slab bridge is the most widely used beam bridge in China. With the increasing traffic volume and traffic load in China, the joints of the hollow-core slab bridge are prone to damage. In this paper, a hollow-core slab bridge with locally curved prestressed tendons is proposed. Based on the static load test of a beam with joints taken from the cross section of a hollow-core slab bridge in practical engineering, a finite element nonlinear analysis is used to simulate the test, and the concrete and interface parameters under the correct analysis results are obtained. Finally, the parameters are applied to the three-beam and two-joint hollow-core slab bridge with a span of 10 m and a finite element analysis is carried out to explore the total failure process and performance improvement effect of the prestressed hollow-core slab bridge. The results show that the interface unit method can successfully simulate the new-to-old concrete interface where the joint is in contact with the precast beam segment. Compared with the static load test results, the analysis error of each finite element model is basically within 15%. Compared with the traditional hollow-core slab bridge, the cracking load, through-joint load, and ultimate load of the prestressed hollow-core slab bridge are increased by 50.0%, 91.7%, and 66.7%, respectively. Under the same load, the stress of the U-bar, the relative deflection of both sides of the joint, and the maximum width of the joint of the prestressed hollow-core slab bridge are lower than those of the traditional hollow-core slab bridge. When the ultimate load is reached, the longitudinal crack lengths of the traditional hollow-core slab bridge and the prestressed hollow-core slab bridge are 0.48 L and 0.4 L, respectively, and the damage degree of the prestressed hollow-core slab bridge is lower than that of the traditional hollow-core slab bridge. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For China Railway Track System (CRTS) I twin-block slab tracks, the interface between the sleeper and track slab is susceptible to damage under the coupled effect of long-term train load and external environment factors. In order to analyze the damage behavior and identify the type of debonding at the interface, this paper established a three-dimensional finite element model and introduced the cohesion zone model and concrete damaged plasticity model to simulate the interface damage and the inner-layer damage of the track slab, respectively. The interface debonding induced by the temperature effect was analyzed, and the debonding types were identified based on the obtained vertical vibration responses of the sleeper surface under the train load. The results reveal that the damage mainly occurs on the bottom and lateral sides at the interface under the temperature load. The track model can be refined further to obtain higher analysis accuracy with acceptable calculation time using the sequential loading method. The 26 damage features derived from the time domain, frequency domain, and time–frequency domain are in good representativeness in reflecting the damage information hidden in the vibration signals. Among them, the peak values (maximum vertical acceleration of the sleeper) are 55.0, 56.7, 60.3, and 61.6 m/s2 for no debonding, debonding on the lateral side, debonding at the bottom, and debonding on the longitudinal side of the interface under train load, respectively. Moreover, the identification accuracy of the debonding type can reach 93.75% combining the particle swarm algorithm and support vector machine. It indicates that the proposed identification method is effective and reliable to provide theoretical guidance for developing scientific maintenance and repair strategies for twin-block slab tracks. [ABSTRACT FROM AUTHOR]

The glacial trough is a common glacier erosion landscape, which plays an important role in the study of glacier erosion processes. In a sharp contrast with the developing river, which is generally meandering, the developing glacial trough is usually wide and straight. Is the straightness of the glacial trough just the special phenomenon of some areas or a universal feature? What controls the straightness of the glacial trough? Until now, these issues have not been studied yet. In this paper, we conduct systematic numerical models of the glacier erosion and simulate the erosion evolution process of the glacial trough. Numerical simulations show that: (1) while the meandering glacier is eroding deeper to form the U-shaped cross section, the glacier is eroding laterally. The erosion rate of the ice-facing slope is bigger than that of the back-slope. (2) The smaller (bigger) the slope is, the smaller (bigger) the glacier erosion intensity is. (3) The smaller (bigger) the ice discharge is, the smaller (bigger) the glacier erosion intensity is. In the glacier erosion process, the erosion rate of the ice-facing slope is always greater than that of the back-slope. Therefore, the glacial trough always develops into more straight form. This paper comes to the conclusion that the shape evolution of the glacial trough is controlled mainly by the erosion mechanism of the glacier. Thereby, the glacial trough prefers straight geometry. [ABSTRACT FROM AUTHOR]

During the operational period, unexpected upstream deformation has been observed in several super-high arch dams located in the alpine and gorge regions. In addition, the phenomenon of the downstream dam deformation monitoring values being apparently smaller than the numerical simulation results appears in some super-high arch dams. This paper focuses on the genetic mechanism of a super-high arch dam's special deformation characteristics. The finite element method (FEM) was used to analyze the effects of solar radiation, valley contraction, and overhanging on super-high arch dam's deformation behavior. First, the influences of solar radiation on the temperature field and deformation characteristics of the super-high arch dam under the shading effects of the mountain and the dam body were investigated. Second, the impacts of valley contraction on the deformation characteristics of the super-high arch dam during the storage period were studied. Subsequently, the impact of the overhanging effect on the super-high arch dam's deformation was explored. Finally, a case study was conducted on the basis of the Jinping I super-high arch dam to evaluate the effectiveness of the proposed analytical method. It is indicated that the dam's special deformation can be explained reasonably. Above all, in order to accurately analyze and predict the deformation characteristics of super high-arch dams in the alpine and gorge regions of Southwest China, solar radiation, valley contraction, and the dam-overhanging effect need to be considered as influencing factors of dam deformation. [ABSTRACT FROM AUTHOR]

The suspension-type monorail (STM) is a new type of rail transit, currently developing rapidly in China. Due to its short construction duration and high terrain adaptability, STM can save large land resources. In particular, by supplementing the traffic systems in large and medium-sized cities, STM can contribute to green tourism projects. However, no systematic study is devoted to the STM transit system in China, and there is still a lack of relevant knowledge and exploration, especially for the special combination system monorail bridge. In view of the real STM bridge, namely a long-span (55 + 100 + 55)-m cable-stayed bridge in this paper, and by applying wind-vehicle-bridge coupling vibration theory, ANSYS finite element method software, and Universal Mechanism multi-body dynamics software, finite element models are established for the bridge and multi-body vehicle, respectively. Furthermore, a co-simulation method is adopted to analyze vehicle-bridge coupling vibrations and ride comfort quality. According to the results, the dynamic responses of the monorail bridge and vehicle are greatly affected by the variation in wind speed, and it is necessary to take measures to decrease system vibrations, thereby ensuring ride comfort quality for vehicle passengers. [ABSTRACT FROM AUTHOR]

Based on the theories of mass conservation and coalbed methane (CBM) adsorption/desorption, this paper first establishes a novel reservoir pressure model for CBM production, following which, the CBM concentration and production models are also proposed. Then, these models are programmed and solved by means of the finite element method. Taking the Hunchun CBM field in Jilin province, China, as an example, the reservoir pressure, gas concentration, and production characteristics under different hydraulic fracture forms are simulated and investigated. In conclusion, the reservoir pressure decreases very rapidly in a small region near the fracture tip, which we called the "reservoir pressure singularity". The existence of a hydraulic fracture greatly reduces the reservoir pressure in the process of CBM exploitation. The permeability sensitivity coefficient of reservoir pressure, Rpk, is defined to quantitatively describe the influence of coal seam permeability on the evolution of reservoir pressure. Rpk decreases logarithmically as the distance from the CBM extraction well increases. The reservoir pressure and CBM recovery rate characteristics in the presence of multiple hydraulic fractures are also investigated. We believe these results could contribute to the design of hydraulic fracturing wells and the evaluation of gas production in a CBM reservoir. [ABSTRACT FROM AUTHOR]

Geological tectonic movement plays a controlling role in the distribution pattern of coalbed methane (CBM) resources. The traditional CBM resource estimation methods use the measured CBM as the overall CBM content and do not consider the influence of geological structure on the nonuniform distribution of CBM resources. In this paper, the geological structure of the Guojiahe coalfield in the northern Yonglong mining area, China, was used as the research background. Based on the precise three-dimensional (3D) seismic interpretation results of the coal seam geological structure and the tested CBM contents at sampling points, a fuzzy comprehensive evaluation method was used to classify the tectonic complexity of the study area, and the CBM contents of different tectonic locations in the tested coal seams and the results determined by the finite element method were analyzed. On this basis, a quantitative relationship between the tectonic complexity index and the amount of CBM resources was established, and finally, a CBM-enrichment prediction model and a CBM resource estimation method for areas with different tectonic complexities were proposed. The agreement between the amount of CBM resources obtained by the estimation method and the actual exploration result is 85.2%; therefore, the proposed method has a theoretical guidance and engineering application value for the exploration and precise development of CBM resources. [ABSTRACT FROM AUTHOR]

Long-span cable-stayed bridge is a typical wind-sensitive structure because of its light weight and great flexibility. The reliability evaluation of the cable-stayed bridge under wind action becomes a key issue during bridge design and operation. In this paper, taking Xiangshan Harbor highway cable-stayed bridge in Ningbo City in China as the engineering background, ANSYS 15.0 is used to build a finite element model of this bridge to explore its aerostatic stability and influencing parameters, then the static wind reliability of this bridge is analyzed. Firstly, considering the structural nonlinearity and the nonlinearity of static wind load comprehensively, the critical wind speed of aerostatic instability of the Xiangshan Harbor cable-stayed bridge is calculated by the internal and external double iteration method. Then the influence of the initial wind attack angle, steel wire breakage rate of the stay cables, static three-component force coefficients, and cable broken position on the static wind stability of this bridge are discussed. Thus, the variation rule of the critical aerostatic instability wind speed is obtained, and the parameter that has the greatest impact on the static wind stability of the cable-stayed bridge in service is determined. Finally, considering the randomness of these key parameters, they are treated as random variables, Latin hypercube sampling (LHS) method is used to obtain samples of random variables to calculate aerostatic instability wind speed for a given sample by self-written calculation program, and on this basis, static wind reliability analysis is conducted by the checking point method, which provides strong support for the static wind risk evaluation of the existing long-span cable-stayed bridge. [ABSTRACT FROM AUTHOR]

An innovative foundation combining a bucket foundation and group piles (BGP) is proposed and investigated in this paper. Sleeve structures are added on the skirt of the mono-bucket, and piles can be inserted through the sleeves and connected with the bucket by grouting. With the same amount of steel, four finite element models of BGPs with different pile diameter and length combinations are established by ABAQUS, as well as a mono-bucket to study the unidirectional bearing capacity and failure mechanism. The results show that the bearing capacity of the BGP with suitable pile length and pile diameter is considerably higher than that of the mono-bucket foundation. Finally, static analysis and natural frequency analysis of the BGP are carried out based on the loading and geotechnical conditions at Yangjiang area of China. The results show that the BGP meet the design requirements, and the new BGP has engineering practicability. [ABSTRACT FROM AUTHOR]

To explore the stability analyses and control methods for surrounding rocks in deep hard rock shafts, this paper is based on field engineering geological surveys and laboratory rock mechanics tests and relies on the main shaft being constructed in the Shaling Gold Mine of China as the engineering background. The quality of the rock mass is evaluated by the Q system, rock mass rating (RMR) and geological strength index (GSI). The mechanical parameters of the surrounding rock mass of the shaft are calculated by using the generalized Hoek–Brown failure criterion, and the main support system is determined based on the rock mass classification system. Based on the finite element method, a two-dimensional plane strain model is constructed to analyze and evaluate the deformation and plastic region range of surrounding rocks for different support systems. On this basis, considering the dilatancy and plastic softening characteristics of hard rock masses, an analytical solution of the stress, strain and plastic region radius of hard rock around shafts in homogeneous media is proposed. Finally, the plastic region of the surrounding rock is measured by the P-wave velocity test method. The results show that after considering the dilatancy and plastic softening characteristics of the rock mass, the numerical simulation, theoretical analytical solution and measured results are basically consistent, and the proposed support system can effectively ensure the stability of the shaft. [ABSTRACT FROM AUTHOR]

In order to avoid the risk of tailing pond failures and to minimize the post-failure losses, it is necessary to analyze the current operation status of tailings ponds, to explore the evolution law of their failure process, to grasp their post-failure impact range, and to propose corresponding effective prevention and control measures. Based on a tailings pond in China, this paper establishes a 1:200 scale indoor model to explore the evolution law of post-failure tailings discharge in a tailings pond under flooded roof conditions; secondly, the finite element difference method and smooth particle fluid dynamics are combined to compare and analyze the post-failure impact area and to delineate the risk prevention and control area. The results of the study show that, during the dam break, the lower tailing sand in the breach is the first to slip, and after forming a steep can, the upper tailing sand in the steep can is pulled to slip, so that the erosion trench mainly develops vertically first, and then laterally. The velocity of the discharged tailing sand will quickly reach its peak value in a short period of time and then decrease to the creeping stage; the front edge of the sand flow is the first to stop moving, and the trailing edge of the tailing sand accumulation depth continues to increase until the end of the dam failure, at which point the initial bottom dam area of the discharge tailing sand flow velocity is the largest. The further the tailings are released from the initial dam, the smaller the accumulation depth and the larger the particle size, and the larger the elevation of the foundation in the same section, the smaller the accumulation depth and the larger the particle size; further, the presence of blocking materials will increase the local tailings accumulation depth. Based on the maximum flow velocity of the discharged tailings and the accumulation depth, the risk area downstream of the tailings pond is divided, so that relocation measures can be formulated. The test results can provide an important reference for the operation and management of similar tailings ponds. [ABSTRACT FROM AUTHOR]

Railway transportation, as an important lifeline during earthquake relief and post-disaster reconstruction, has an extremely significant role. The study of track irregularity caused by earthquakes is the basis for ensuring traffic safety after their occurrence. In this paper, a finite element model of a five-span simply supported high-speed railway beam bridge with the China Railway Track System (CRTS) II was established and an experimental verification was performed. Eighty arbitrarily selected seismic waves were extracted from the Pacific Earthquake Engineering Research Center (PEER) strong ground motion database and a nonlinear time-history analysis was performed on the finite element model. The frequency–domain distribution law of earthquake-induced track irregularities was studied. A stable target earthquake-induced track irregularity spectrum model was constructed, and its expression was fitted. According to the results, in the case of transverse earthquakes, the rails experienced noticeable alignment irregularity and cross-level irregularity, while the amplitude of the gauge and vertical irregularity were relatively small. The target irregularity spectrum has a higher amplitude in the low-frequency components. When peak ground acceleration (PGA) was low, earthquake-induced track irregularity was not obvious, but the deteriorating effects of earthquakes on track irregularities increased significantly with increasing PGA. [ABSTRACT FROM AUTHOR]

Temperature is one of the main loads of super-high arch dams. (1) Background: a super-high arch dam in southwest China was taken as an example in this paper and the temporal-spatial evolution law of dam temperature was analyzed based on the monitoring data. (2) Methods: the finite element simulation analysis method was adopted to invert the boundary conditions of temperature on the upstream surface and the thermal parameters of the concrete, and the temperature evolution process of the arch dam in long-term operation was simulated and analyzed. After the distribution characteristics of the designed reservoir water temperature and the actual reservoir water temperature were compared, the difference in the temperature field of the arch dam during the impoundment and operation under the designed and actual conditions was studied. (3) Results: the temporal-spatial evolution law of the temperature in the dam operation period accords with the conventional knowledge, and the calculated value through simulation feedback is in good agreement with the monitoring value, which can reflect the actual temperature field distribution of the dam. (4) Conclusions: under the design condition, the dam temperature rose slowly after closure grouting and then tended to be stable. Under the actual condition, the temperature rose by 7.1~9.2 °C after closure grouting, reached the highest temperature in about 8~12 years, and fell back to a stable temperature in 40~80 years. [ABSTRACT FROM AUTHOR]

Frame structures with exterior verandahs, which are mostly built in densely populated areas such as teaching buildings and dormitories in southern China, are a special form of frame structure that must continue to be developed. However, compared with other frame structures in many post-earthquake fields, this type of building designed following the Chinese code has demonstrated poor seismic performance, leading to a significant number of casualties and property losses. Therefore, to complement the design requirements of this structural type in the present Chinese code, the seismic performance of this structural type needs to be improved and optimized. A typical double-span RC frame structure with an exterior verandah in the Lushan Earthquake as the structure prototype was selected in this paper. PKPM software is used to obtain design information for the structure prototype, and the finite element model is established by utilizing ABAQUS software for simulation and analysis. A series of various optimal conditions are created at the base of the structure prototype's simulation results, and a thorough investigation of the structural seismic performance under each condition is performed. Eventually, suggestions and proposals for future Chinese codes concerning the structurally optimum design of this structural type are provided. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• We have devised a composite gear transmission system, which comprises a RV reducer, two parallel shaft transmissions, and a planetary gear transmission. • A rescue module has been integrated into the driving system to ensure the necessary rescue operations for the manipulator. • The structural configuration of the relevant shells has been developed, with comprehensive explanation on dimensions, manufacturing methodology and strength assessment. • A detailed exposition on the internal architecture and rotational capabilities of these joints has been provided. • An effective internal cable routing scheme for the root joints has been proposed. This study concentrates on the engineering design and analysis of the root joints for the CFETR Multi-Purpose Overload Robot (CMOR), a crucial component in the China Fusion Engineering Test Reactor (CFETR). The CFETR tokamak is an engineering test reactor in China for magnet confinement fusion research. CMOR is a 7-DOF manipulator characterized by heavy-load capacity, high precision, and compact structures, designed for internal maintenance inside the CFETR. This presents significant challenges in its design. The design of the root joints is significant for the CMOR. This paper provides an in-depth exploration of the engineering design and analysis of the root joints. It offers a thorough explanation of the driving systems' design, including an integrated rescue module to address potential manipulator faults. Additionally, this paper delves into the conceptual design and manufacturing schemes of the corresponding shells, which are validated under various loading conditions—including regular and earthquake scenarios—through finite element analysis. The assembled root joints' internal structure and cable routing scheme are also discussed in-depth. This research provides valuable insights for future joint designs of the CMOR heavy load manipulator, advancing maintenance operations for fusion reactors. [ABSTRACT FROM AUTHOR]

Recycled concrete self-insulating blocks (RCSBs) are an economic and environmentally friendly load-bearing building material that can save energy. In China, there is almost no systematic evaluations focusing on the shear performance of RCSB walls. To realize the effective utilization of RCSB, this paper makes a series of experimental research and theoretical analysis on the shear performance of 72 standard RCSB wall specimens. The key factors such as shear failure characteristics, shear strength calculation formula, and shear compression failure criterion are analyzed. The test results show that the shear strength of RCSB walls is higher than that of ordinary concrete block wall. Recommended formulas for the shear strength of RCSB walls are given, taking into account the actual situation, and having certain safety and reliability. The measured shear-pressure correlation curve of RCSB walls is given, including three modes of shear-friction, shear-compression, and diagonal compression. Additionally, an elastoplastic finite element analysis of RCSB walls is performed by separating the block model from the mortar model by using ABAQUS, which can accurately simulate the shear behavior of RCSB walls. [ABSTRACT FROM AUTHOR]

The Yinxi Railway is located in the western region of China. As a high speed railway line connecting Yinchuan-Xi'an, which is of great significance for the construction of transportation facilities in western China. Because the Yinxi Railway passes through loess areas, cement fly-ash gravel (CFG) long piles and cement-soil compacted (CSC) short piles are used for the subgrade treatment method. In Part I of this paper, experimental results relating to the effect of the composite foundation were presented. In Part II, finite element analysis are undertaken of the influence of the change of physical parameters of the composite subgrade caused by different cement content on the subgrade performance. The results show that the performance of the composite subgrade can be fully achieved under the condition of achieving the best cost performance by selecting the appropriate ratio of cement-modified soil, which provides a certain reference for the optimization of design parameters of similar composite subgrade projects in the future. [ABSTRACT FROM AUTHOR]

The ergonomics on body pressure distribution of latex product design is the future trend in bedding product design. The numerical simulation of latex pillow compression performance is critical for the optimal design of bedding products. This paper reports the use of the finite element method to simulate the compression performance of latex foam and the design of latex pillows based on the pressure distribution and displacement changes of the human pillow system. The compression performance, shear performance and tensile performance of the latex foam are tested, and the stress and strain images of three mechanical experiments are obtained. Combined with the experimental results, three methods of 'hyper foam test data, hyper foam model parameter method and low-density foam method' were used to perform uniaxial compression simulation on bedding latex foam using the finite element software ABAQUS. The simulation results and experimental values were fitted and analyzed. The analysis found that the low-density foam simulation method has the largest R2, which is 0.9871, and the simulation result is the most accurate. The optimal simulation method was selected to simulate the dynamic pressure changes and cervical displacement of the human head and latex pillow models, as well as the simulation experiments with latex pillows of different heights. The curve is fitted to obtain the second-order polynomial equations of pressure and cervical socket displacement. In contrast, it can be concluded that latex pillow products with a neck height of 100 mm are better for the supine position of younger adult women in China. [ABSTRACT FROM AUTHOR]

Steel slag (SS) is industrial waste, and there is a large amount of SS to be treated in China. Its disposal generates severe environmental pollution. One of the best ways to use SS is as a road base material. This paper reviews the possibility of using SS in semi-rigid base and evaluates the performance of SS base course. The interaction between three stabilizers (cement, lime–fly ash, and cement–fly ash) and SS is analyzed, and the influence of modifier content on the performance of base course is evaluated. The potential laws between SS, curing time, and unconfined compressive strength, as well as drying shrinkage and temperature shrinkage, are discussed and their effects on the performance of the base course are revealed. The finite element method, discrete element method, and molecular dynamics can be used to analyze the freeze-thaw, rutting resistance, and crack development of SS base. In addition, compared with traditional macadam base, the CO2 emissions for the use of SS base are slightly more, one of the disadvantages of its use in production, transportation, and compaction. However, considering the overall mechanical, economic, and environmental benefits, it is recommended to use SS in semi-rigid base course. The future research scope of SS as base material is suggested. [ABSTRACT FROM AUTHOR]

In recent years, with the rapid development of China's construction industry, assembled buildings have become more and more common. In this context, China attaches great importance to the development of assembled buildings and has introduced a series of policies to support the promotion of assembled buildings. Assembled building technology has become relatively mature in some developed countries. From their experience, it can be learned that the construction of an assembled concrete structure technology system is the basis for the promotion of assembled concrete buildings. A factory-based production model enables prefabricated concrete elements to be produced to a good quality. The key to the technical system for the construction of assembled concrete structures is the connection of the prefabricated elements. At the same time, it is essential to consider not only the reliability of the structural performance of the assembled concrete structure but also the cost and safety of the design, production, transport, and construction processes. In fact, the safety of an assembled concrete structure depends to a large extent on whether the nodal connection technology meets the design and quality requirements. Unlike conventional cast-in-place concrete structures, the key nodes of assembled concrete structures have a greater impact on the mechanical properties of the load transfer. In other words, this influence is directly related to the design of the prefabricated elements. Hence, the mechanical properties of precast nodal joints, such as good stiffness, are essential for the structural safety of assembled buildings. In the case of assembled buildings, the correct form of nodal connection is decisive in ensuring that the connection meets the design and service requirements. In addition to this, the correct nodal connection form will ensure that the design life is maintained. The uneven quality of many prefabricated components has limited the promotion of assembled concrete structures and is a key constraint to their development. At this stage, there are no uniform standards for quality control systems and measures on site in China, and the level of technical management is not yet fully mature. What is more, the overall quality of construction personnel is not high enough, which might lead to some frequent issues with the quality of connections in the field during the actual construction process. As a result, the development of assembled concrete structures urgently requires perfect construction management standards as a guide for on-site joint construction, so as to guarantee the quality level of on-site joint construction. In order to study the force performance of assembled concrete structures, this paper establishes an analytical model for assembled concrete buildings based on the intelligent finite element method. To be specific, this research introduces artificial neural network theory into the structural analysis of assembled buildings and transports it into the finite element solution, thus forming an intelligent finite element method. [ABSTRACT FROM AUTHOR]

Karst caves are widely distributed in southwest China, causing difficulties and disasters for tunnel construction. To better detect the krast caves in front of the tunnels under construction using the transient electromagnetic method, in this paper we propose a 3-D finite element method to simulate the multi-parameter transient electromagnetic response of unfavorable geological bodies in a wholespace. First, the models of vertical water-filled faults, water-filled caves and complex geological bodies in front of the tunnel face are established. The horizontal electric field component and the vertical magnetic field component at different time in the whole-space are researched. Secondly, the electromagnetic response features of the caves with different resistivity, buried depths and scales are studied. We found that the resistivity of the target body is 10 times larger than that of the surrounding rocks, and the anomaly amplitude increases obviously with the growing distance from the target body. The deeper the buried depth, the later the anomaly appears and the smaller the anomaly amplitude. The larger the target size, the longer the transient electromagnetic response delay and the larger the anomaly amplitude. We arranged a measuring line on the tunnel face. The full-time apparent resistivity section shows the position and characteristics of the low-resistivity anomalous body, indicating that the transient electromagnetic method (TEM) has obvious advantages in detecting the low-resistivity body in front of the tunnel face. Finally, the TEM is successfully applied to the advanced detection of a karst tunnel to get the electrical distribution of the surrounding rocks in front of the tunnel face. According to the geological conditions of the excavated tunnel, the validity of the TEM in the tunnel advanced prediction is verified. [ABSTRACT FROM AUTHOR]