作者机构：
[Zhengyi Cao] Nuclear Industry Jinhua Survey and Design Institute Co., Ltd., Jinhua 321000, China;These authors contributed equally to this work as co-first author.;School of Civil Engineering and Engineering Management, Guangzhou Maritime University, Guangzhou 510725, China;School of Civil Engineering, Central South University of Forestry and Technology, Changsha 410018, China;Authors to whom correspondence should be addressed.
通讯机构：
[Zhenzhen Wei; Gang Huang] A;Authors to whom correspondence should be addressed.<&wdkj&>School of Civil Engineering, Central South University of Forestry and Technology, Changsha 410018, China
摘要：
In order to investigate the dynamic response of embankment slopes supported by wooden frame beams and bamboo anchor rods under train loading, this study conducted model tests on embankment slopes supported by wooden frame beams and bamboo anchor rods and carried out three-dimensional numerical simulations of the slopes. This study focused on analyzing the effects of train loading frequency, the peak value difference, and the peak value of the soil pressure on the embankment slopes. This study also analyzed the horizontal displacement of the slope surface, the internal forces in the support structure, and the slope safety factor. The results indicated the following: (1) The increase in loading frequency from 2 Hz to 3 Hz resulted in a significant increase in dynamic soil pressure, with a smaller increase observed upon further frequency increments. Moreover, increasing the load or peak value difference led to an overall increase in the maximum dynamic soil pressure. (2) Under various loading conditions, the axial force in the top anchor rod was significantly greater than that in the middle anchor rod. Additionally, the axial force in the rod body exhibited a pattern of larger forces near the anchorage end and smaller forces near the anchor head. The location of the maximum bending moment in the anchor rod transitioned from the anchor head to the anchorage end as the slope depth increased. The bending moment of the anchor rod increased with the loading frequency but decreased with an increase in the peak value, showing a minor influence from the upper and lower peak values. (3) With the presence of this support system, the slope safety factor increased by 20.13%. A noticeable reduction in the horizontal displacement of the slope surface was observed, with the greatest reduction in the top slope area, followed by the slope angle.
期刊：
Journal of Building Engineering,2024年86:108748 ISSN：2352-7102
通讯作者：
Xiaoming Ma
作者机构：
[Liqiang Jiang; Jianguang He] School of Civil Engineering, Central South University, Changsha, 410075, China;[Zhibin Zhang; Hua Yang] School of Civil Engineering, Chang'an University, Xi'an, 710061, China;[Yi Hu] School of Civil Engineering, Central South University of Forestry and Technology, Changsha, 410004, China;[Zongping Chen] College of Civil Engineering and Architecture, Guangxi University, Nanning, 530004, China;[Xiaoming Ma] School of Civil Engineering, Central South University, Changsha, 410075, China<&wdkj&>School of Civil Engineering, Chang'an University, Xi'an, 710061, China
通讯机构：
[Xiaoming Ma] S;School of Civil Engineering, Central South University, Changsha, 410075, China<&wdkj&>School of Civil Engineering, Chang'an University, Xi'an, 710061, China
摘要：
This paper proposes a novel type of cold-formed steel (CFS) built-up closed L-shaped section column (CSBC-L). The CSBC-L is a part of the novel special built-up column prefabricated modularized mid-rise CFS structural system (SPMM-CFS), and it can be used to compose the corner-column modulus. The CSBC-L can install sheathing walls in two crossed directions without any other connecting components, and it exhibits large torsional stiffness and inertia moment. This paper conducted experimental investigations on the compressive behavior of CSBC-L with different configurations. Totally 18 test specimens with different plate thicknesses, web heights and screw spacings were designed and tested. The results show that the ultimate strength of CSBC-L can be effectively improved with increasing the web height and plate thickness. Finite element (FE) models were developed for the test specimens, and the failure modes as well as the nonlinear load‒displacement curves were simulated and validated. Finally, the effective width method (EWM) and direct strength method (DSM) are used to predict the ultimate strength of the CSBC-L specimens in AISI S100-16 and EN 1993-1-3. It is found that the DSM is more accurate to predict the axial compressive ultimate strength, and most of the errors are less than 10%.
期刊：
Geotechnical and Geological Engineering,2024年42(2):1505-1518 ISSN：0960-3182
通讯作者：
Chang-Ping Wen
作者机构：
[Huan-Xia Ren; Xiang Chen] School of Civil Engineering, Changde Vocational Technical College, Changde, People’s Republic of China;[Chang-Ping Wen] School of Civil Engineering, Central South University of Forestry and Technology, Changsha, People’s Republic of China
通讯机构：
[Chang-Ping Wen] S;School of Civil Engineering, Central South University of Forestry and Technology, Changsha, People’s Republic of China
期刊：
Theoretical and Applied Climatology,2024年155(1):117-129 ISSN：0177-798X
通讯作者：
Wang, HQ
作者机构：
[Wang, HQ; Liu, Xinyu; Wang, Hanqing; Zhu, Dongnan; Liu, Zhenming; He, Junyi] Univ South China, Sch Civil Engn, Hengyang, Peoples R China.;[Wang, HQ; Liu, Xinyu; Wang, Hanqing; Zhu, Dongnan; Liu, Zhenming; He, Junyi] Natl & Local Joint Engn Res Ctr Airborne Pollutant, Hengyang, Peoples R China.;[Wang, HQ; Wang, Hanqing] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha, Peoples R China.
通讯机构：
[Wang, HQ ] U;Univ South China, Sch Civil Engn, Hengyang, Peoples R China.;Natl & Local Joint Engn Res Ctr Airborne Pollutant, Hengyang, Peoples R China.;Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha, Peoples R China.
关键词：
WRF;Deep learning;Downscaling
摘要：
The Weather Research and Forecasting (WRF) model improves the accuracy of climate prediction and obtains meteorological parameters for fine grids; however, fine-grid climate predictions for different time periods and regions often consumes a great amount of computational resources. In this letter, the Multi Residual Attention Generative Adversarial Network (MRA-GAN) is proposed based on the generative adversarial network; the technique is applied to restore a simulated image from a coarse-grid WRF model to a simulated image from a fine-grid WRF model. The fine-grid image generated by MRA-GAN is very similar to the original fine-grid image. When compared with Super-Resolution Wasserstein Generative Adversarial Network with Gradient Penalty (SRWGAN-GP), the average of peak signal-to-noise was improved by approximately 0.54dB, and the average structural similarity index was improved by approximately 3%. After comparing the downscaling results of temperature, wind speed, and relative humidity of various models with the original data, the results show that MRA-GAN has the highest correlation, the lowest data dispersion, and the smallest data error. The trained network model was able to efficiently transform the coarse-grid meteorological fields from different time periods and different simulation variables into fine-grid meteorological fields, and it greatly reduced the computational workload.
摘要：
The loading intermittence duo to the time interval between adjacent passing trains is conducive to improving the dynamic stability of railway subgrade, but this intermittence effect is always ignored in existing experimental studies on the dynamic characteristics of subgrade fillers in which a continuous cyclic loading method was adopted to simulate the long-term train-induced loading on subgrade. This paper aims to study the backbone curves of subgrade silty filler under intermittent train-induced loading, considering the time interval between adjacent passing trains. By conducting a series of intermittent cyclic triaxial tests on silty filler, the backbone curves of each loading stage were constructed, and the effects of loading intermittence on the backbone curves were elaborated. The experiment results indicate that the loading intermittence enhances the resistance of subgrade silty filler to the dynamic loading and is conducive to the upward deviation of the backbone curves. The loading intermittence could effectively increase the ultimate value of dynamic stress amplitude that the silty filler could bear under cyclic loading, but has little effect on the maximum/initial resilient modulus. The backbone curves increase approximately linear under the states of plastic shakedown and plastic creep, but show significant nonlinearity after including the incremental collapse samples. Hyperbolic models for backbone curves such as H-D model and its improvement model could be adopted to characterize the backbone curves of silty filler under intermittent loading, and the normalization of H-D model was also discussed to integrate the influencing factors (i.e., moisture content and confining pressure) of the backbone curves.
摘要：
This article presents a new theoretical method for the torsional-flexural vibration response of a thin-walled beam with closed cross sections under a uniformly distributed moving load. Based on Vlasov's theory and restrained torsion theory, a comprehensive equation of motion for torsional flexural vibration is established by considering the effects of additional torque caused by the change of the shear center and the center of mass and the warpage coefficient. Using the Fourier transform, Laplace transform, and their inverse transformations, the torsional-flexural vibration response expression of thin-walled beams with closed cross-sections under a uniformly distributed moving load was derived. The results calculated by the analytical solutions in this study were compared with those from finite element method, demonstrating the reliability and superiority of the analytical solutions. Compared with the method that ignores the warpage coefficient, the lateral displacement and torsion angle of the beam calculated by the proposed theoretical method decreased by more than 12.00%. The effect of the cross-sectional properties on the natural frequency of the torsional-flexural vibration of thin-walled beams is analyzed, and the results show that the moment of inertia and mass per unit length have a considerable influence on the torsional-flexural frequency, which increases with the moment of inertia and decreases with an increase in the mass per unit length. The influences of the load magnitude, load velocity, and load eccentricity on the dynamic response were further investigated. According to the results, the lateral displacement of the beam increased significantly with increases in the load eccentricity and load magnitude. In practical engineering, the conclusions of this study can be used to limit the torsional-flexural vibration response of simple maglev support bridges to ensure the safety of vehicles and passengers.
期刊：
Building and Environment,2024年249:111127 ISSN：0360-1323
通讯作者：
Deng, QH
作者机构：
[Zhao, Jinping; Wang, Hanqing] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha, Peoples R China.;[Zhao, Jinping; Wang, Hanqing] Cent South Univ Forestry & Technol, Hunan Engn Res Ctr Full Life Cycle Energy Efficien, Changsha, Peoples R China.;[Ou, Dengsong; Wang, Yan] Cent South Univ, Sch Energy Sci & Engn, Changsha, Hunan, Peoples R China.;[Wang, Yan] Wuhan Hanyang Municipal Construct Grp Co Ltd, Wuhan, Peoples R China.;[Li, Yuguo] Univ Hong Kong, Dept Mech Engn, Hong Kong, Peoples R China.
关键词：
Cold exposure;Hypothermia;Body core temperature;Thermoregulatory fatigue;Survival time
摘要：
Background: Extreme temperatures are becoming increasingly common due to global warming. Extreme cold and heat events lead to an increase in mortality rates. More deaths occur in cold weather as a result of hypothermia. However, the change progress of body core temperature and the survival time during cold exposure has yet to be extensively studied. Objectives: To establish a mathematical thermoregulatory model for prolonged cold air exposure and to propose a method for predicting survival time under sedentary conditions. Methods: We extended the classical multi -segment multi -node human thermoregulatory model by considering the effects of thermoregulatory fatigue on shivering and vasoconstriction based on the variable setpoint theory. The core threshold temperatures and the sensitivity of the responses decreased with the degree of fatigue (fa). The model was then used to systematically examine the effects of environmental parameters on the time course of body core temperature in the development of fatal hypothermia. A new wind chill index was constructed based on the simulated data of our thermoregulatory model to estimate the survival time. Results: Our extended thermoregulatory model predicted that during prolonged cold air exposures, body core temperature would decrease in three distinct stages: an initial decrease due to uncompensated cooling load, an equilibrium plateau due to shivering, and a final rapid drop due to thermoregulatory fatigue. Fatal hypothermia occurred at the third stage due to impaired shivering and vasoconstriction caused by fatigue. Lower air temperature and higher air speed can accelerate the occurrence of hypothermia. We proposed a predictive equation for survival time, i.e., the maximum endurance time before fatal hypothermia occurs, which is an exponential function of the wind chill index, and the newly defined wind chill index considers the contribution from both air temperature and air speed. Conclusions: We suggest a new thermoregulatory model to predict the fatal hypothermia due to thermoregulatory fatigue during cold air exposure. We proposed a survival time chart based on a new wind chill index, which can be used to alert the early risk of fatal hypothermia during extreme cold events.
作者机构：
School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, China;College of Ocean Engineering and Energy, Guangdong Ocean University, Zhanjiang, China;School of Civil Engineering, Central South University of Forestry and Technology, Changsha, China;Hunan Engineering Research Center of Full Life-cycle Energy-efficient Buildings and Environmental Health, Changsha, China;[Dan Li] School of Food Science and Engineering, Central South University of Forestry and Technology, Changsha, China
通讯机构：
[Hanqing Wang; Jinping Zhao] S;School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, China<&wdkj&>School of Civil Engineering, Central South University of Forestry and Technology, Changsha, China<&wdkj&>Hunan Engineering Research Center of Full Life-cycle Energy-efficient Buildings and Environmental Health, Changsha, China<&wdkj&>School of Civil Engineering, Central South University of Forestry and Technology, Changsha, China<&wdkj&>Hunan Engineering Research Center of Full Life-cycle Energy-efficient Buildings and Environmental Health, Changsha, China
关键词：
Food freezing;Magnetic field assistance;Freezing curve;Ice crystal;Shelf life;Low-temperature preservation
摘要：
Freezing is a widely used technology for food processing that not only lowers the temperature of food below its freezing point but also inhibits microbial activity and slows down biochemical reactions to enable long-term preservation. However, the freeze thawing cycle can cause various chemical and physical damages to food, which are the main influencing mechanisms of low-temperature preservation. The size of ice crystals determines the degree of physical damage to cells, which has a significant impact on the freezing quality. Magnetic field (MF) treatment is a physical method that has been found to be milder, more effective, and have no obvious side effects compared to chemical treatments. Numerous studies have reported that MF promotes the cold storage of food, prolongs shelf life, inhibits ice crystal nucleation, increases supercooling, accelerates freezing speed, and reduces ice crystal sizes significantly. However, the role of MF in ice nuclei formation is still unresolved, and there are inconsistencies in research results and a lack of clear understanding of its potential mechanism. This paper aims to introduce the influence of MF on the formation and growth of ice crystals, summarize freezing curves on water and salt solutions, and analyze MF applications from two aspects: the thermodynamic mechanism and molecular dynamics point of view for freezing processes. Additionally, it discusses the problems encountered in recent researches and presents future development trends. The conclusion can be drawn that MF demonstrates great application potential in the field of freezing processes and food quality attribute evaluation. However, many questions remain with little consensus in the literature regarding their roles, and the mechanism of action is not unified. The application of MF in food freezing processes is still challenging. This paper hopes to provide guidance for future work on food freezing and contribute to the advancement of this field.
期刊：
IEEE GEOSCIENCE AND REMOTE SENSING LETTERS,2024年21:1-5 ISSN：1545-598X
作者机构：
[Yushan Zhou] School of Geosciences and Info-physics, Central South University, Changsha, China;School of Civil Engineering, Central South University of Forestry and Technology, Changsha, China;Hunan Key Laboratory of Remote Sensing Monitoring of Ecological Environment in Dongting Lake Area, Hunan Natural Resources Affairs Center, Changsha, China;[Meng Duan] School of Civil Engineering, Central South University of Forestry and Technology, Changsha, China<&wdkj&>Hunan Key Laboratory of Remote Sensing Monitoring of Ecological Environment in Dongting Lake Area, Hunan Natural Resources Affairs Center, Changsha, China
摘要：
The digital elevation model (DEM) differencing method has been widely used for quantifying land surface change, especially in the field of glacier mass change. However, when the global DEM datasets are used to estimate large-scale glacier changes, the superposition effect of multisource errors makes it difficult to remove the errors in the differencing maps using the existing method based on manually supervised correction. In this letter, to solve this issue, we propose a new stepwise correction method with an adaptive data partitioning strategy. The first step is to perform global spatial detrending, followed by global coarse co-registration. Subsequently, an initial data partitioning scheme based on the quadtree partitioning technique and relying on terrain slope is proposed. Furthermore, a parameter, i.e., the standardized standard deviation (SSTD) based on elevation changes, is used to further update the partitioning scheme. Finally, for each segmented data block, local spatial detrending is performed, followed by precise local co-registration. The proposed method was tested in the Pamir Plateau and the Tianshan River valley, based on the Shuttle Radar Topography Mission (SRTM) C-band and X-band DEMs and the Copernicus DEM. The final results show that the various types of error can be automatically and effectively removed, and that the normalized median absolute deviation (NMAD) and long-range correlation variance in ice-free areas show an improvement of 10% and 24% and 37% and 60% for the two study regions, respectively, demonstrating the good performance of the proposed method.
期刊：
Construction and Building Materials,2024年412:134749 ISSN：0950-0618
通讯作者：
Dong, JL
作者机构：
[Zhang, Cong; Wen, Changping; Zhang, Qishu] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410004, Peoples R China.;[Dong, Junli; Leng, Wuming] Cent South Univ, Sch Civil Engn, Changsha 410075, Peoples R China.;[Zhou, Zhenhua] Chinese Acad Sci, Inst Rock & Soil Mech, State Key Lab Geomech & Geotech Engn, Wuhan 430071, Peoples R China.;[Zhou, Zhenhua] Univ Chinese Acad Sci, Beijing 100049, Peoples R China.
通讯机构：
[Dong, JL ] C;Cent South Univ, Sch Civil Engn, Changsha 410075, Peoples R China.
关键词：
Prestressed subgrade;Track irregularity;Heavy-haul train;3D finite element model;Dynamic stress
摘要：
To explore the dynamic transient characteristics induced by passing heavy-haul trains in newly-developed prestressed subgrade, two three-dimensional finite element models were constructed in the time domain using ABAQUS software. These models are categorized as train-track-prestressed subgrade and train-track-unreinforced subgrade. The numerical models also incorporated the vertical track irregularity commonly found in heavy-haul railways. The investigation aims to discern the dynamic stress response differences in both types of subgrades under three distinct train axle loads. Model validation occurred through comparisons with field tests gathered from various heavy-haul railways in China, as well as analogous numerical simulation cases. The findings indicate that track irregularity results in an asymmetric distribution of dynamic stress on the subgrade surface beneath both left and right rails, aligned transversely with the subgrade centerline. Additionally, this asymmetry is notably pronounced. The peak dynamic stress on the subgrade surface beneath the rails for both subgrades increases with escalating train axle loads. However, the prestressed reinforcement structure (PRS) effectively modulates this phenomenon, with the controlling advantage intensifying as train axle load increases. The average dynamic stress level in the prestressed subgrade is marginally lower than in the unreinforced subgrade within the roadbed layer beneath rails. Furthermore, train axle loads amplify the variation level of dynamic stress in the subgrade. However, the variable coefficient of dynamic stress in the prestressed subgrade is less than in the unreinforced subgrade, suggesting that PRS contributes positively to maintaining subgrade dynamic stability. In terms of the longitudinal distribution of peak dynamic stress, both subgrades exhibit normal distribution at varying depths within the roadbed layer. Lastly, the additional dynamic stress in prestressed steel bars also rises with increasing train axle loads. Nonetheless, it remains substantially lower than the static target pre-tensile stress. Moreover, the dynamic responses of prestressed steel bars in different rows attenuate as depth increases away from the subgrade top surface. In summary, this study establishes that PRS significantly enhances the dynamic stability of railway subgrade.
期刊：
Indian Geotechnical Journal,2024年:1-10 ISSN：0971-9555
通讯作者：
Liu Sisi
作者机构：
[Wang Shuisheng; Liu Sisi] School of Civil Engineering, Central South University of Forestry and Technology, Changsha, China;[Li Mouming] China Nonferrous Metals Changsha Survey, Design and Research Institute Limited, Changsha, China;[Yu Yi] Shantou Construction Engineering Quality and Safety Center, Shantou, China
通讯机构：
[Liu Sisi] S;School of Civil Engineering, Central South University of Forestry and Technology, Changsha, China
关键词：
Root–soil composite;Flexible stiffened model;Root weight density RMD;Vetiver
摘要：
Root mass density (RMD) is introduced as the core parameter in the flexible friction-stiffened model of the root–soil complex to build the improved model so that the parameter values have better operability. First, "RMD/k" was used to replace the original model parameter "A/n," and the improved flexible friction stiffened model with RMD as the core was derived in the flexible state. Then, the root distribution test, single-root tensile test, and shear test of the root–soil composite were carried out to investigate the root distribution pattern, root tensile resistance and tensile strength variation characteristics, and root–soil composite shear strength characteristics by using vetiver as the test sample. It is concluded that the increase in shear strength reaches the maximum when the shear deformation angle (β) is equal to the internal friction angle (φ) and the RMD variation characteristics of the improved model were obtained. The calculated value of the enhanced model is compared with the measured data and the original model, and the results were similar.
作者机构：
[Xu, Linrong; Li, Yongwei; Shang, Yonghui; Xu, LR] Cent South Univ, Sch Civil Engn, Changsha 410075, Peoples R China.;[Xu, Linrong; Li, Yongwei; Xu, LR] Cent South Univ, Natl Engn Res Ctr High Speed Railway Construct Te, Changsha 410075, Peoples R China.;[Chen, Shuyang] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410004, Peoples R China.
通讯机构：
[Xu, LR ] C;Cent South Univ, Sch Civil Engn, Changsha 410075, Peoples R China.;Cent South Univ, Natl Engn Res Ctr High Speed Railway Construct Te, Changsha 410075, Peoples R China.
关键词：
machine learning;earthquakes;debris flow susceptibility;convolutional neural network;deep neural network;watershed unit
摘要：
Jiuzhaigou is situated on a mountain-canyon region and is famous for frequent tectonic activities. An abundance of loose co-seismic landslides and collapses were produced on gullies after the Jiuzhaigou Earthquake on August 8, 2017, which was served as material source for debris flow in later years. Debris flow appears frequently which are seriously endangering the safety of people's lives and properties. Even the earliest debris flow appeared in areas where no case ever reported before. The debris flow susceptibility evaluation (DFSE) is used for predicting the areas prone to debris flow, which is urgently required to avoid hazards and help to guide the strategy of preventive measures. Therefore, this work employs debris flow in Jiuzhaigou to reveal the characteristics of disaster-pregnant environment and to explore the application of machine learning in DFSE. Some new viewpoints are suggested: (i) Material density factor of debris flow is first adopted in this work, and it is proved to be a critical factor for triggering debris flows by sensitivity analysis method. (ii) Deep neural network and convolutional neural network (CNN) achieve relatively good area under the curve (AUC) values and are 0.021-0.024 higher than traditional machine learning methods. (iii) Watershed units combined with CNN-based model can achieve more accurate, reliable and practical susceptibility map. This work provides an idea for prevention of debris flow in mountainous lands.
摘要：
Sialic acid (SA) is a kind of functional monosaccharide which exists widely in edible bird's nest (EBN), milk, meat, mucous membrane surface, etc. SA is an important functional component in promoting brain development, anti-oxidation, anti-inflammation, anti-virus, anti-tumor and immune regulation. The intestinal mucosa covers the microbial community that has a significant impact on health. In the gut, SA can also regulate gut microbiota and metabolites, participating in different biological functions. The structure, source and physiological functions of SA were reviewed in this paper. The biological functions of SA through regulating key signaling pathways and target genes were discussed. In summary, SA can modulate gut microbiota and metabolites, which affect gene expressions and exert its biological activities. It is helpful to provide scientific reference for the further investigation of SA in the functional foods.
期刊：
Journal of Energy Storage,2024年78:109965 ISSN：2352-152X
通讯作者：
Mei, SJ
作者机构：
[Mei, Shuo-Jun] Sun Yat Sen Univ, Sch Atmospher Sci, Zhuhai, Peoples R China.;[Hu, Jiang-Tao] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha, Hunan, Peoples R China.;[Mei, Shuo-Jun; Mei, SJ] Sun Yat Sen Univ, Haiqin Bldg 2, Zhuhai 519082, Guangdong, Peoples R China.
通讯机构：
[Mei, SJ ] S;Sun Yat Sen Univ, Haiqin Bldg 2, Zhuhai 519082, Guangdong, Peoples R China.
关键词：
Salt gradient solar pond;Stability analysis;Thermosolutal convection simulation;Porous layer;Thermal energy storage
摘要：
The salt gradient solar pond (SGSP) can capture and store a large amount of solar energy for a long time, making it an efficient and economical solar energy facility. The long-term operational stability of SGSP can be damaged by interface erosion, which is caused by thermosolutal convection. Attaching porous layers is a promising approach to slow down interface erosion. In this study, we simulated the unsteady thermosolutal convection in SGSP with Lattice Boltzmann methods (LBM). The effects of a porous layer on salinity gradient stability are analyzed with boundary equilibrium and marginal criterion. The simulation results show that the SGSP becomes thermally unstable when the interface erosion begins. By attaching a porous layer to the bottom surface, the convective flow is weakened and the instability in SGSP is reduced. The stability analysis shows that the thermally unstable state in SGSP transits into a theoretically stable state by attaching a porous layer. As the stable state is prolonged, the fluid temperature in the storage layer increases. We also find that reducing the permeability of the porous layer or increasing the layer thickness prolongs the stable state. This study helps to improve future SGSP design and promote its engineering application.
作者：
Lei Chen;Sanling Zhang;Lei Liu;Zhiwu Yu;Peng Liu*;...
期刊：
Coatings,2024年14(3):369- ISSN：2079-6412
通讯作者：
Peng Liu
作者机构：
[Lei Chen] China Railway No. 10 Engineering Group Co., Ltd., 2000 Shunhua Road, Jinan 250101, China;School of Civil Engineering, Central South University of Forestry and Technology, 498 Shaoshan Road, Changsha 410004, China;[Sanling Zhang; Xiang Cheng; Jingxiang Huang] School of Civil Engineering, Central South University, 22 Shaoshan Road, Changsha 410075, China;School of Physical and Technology, Yili Normal University, 448 Jiefang West Road, Yining 835000, China;[Ning Zhang; Sasa He] Hunan Zhongda Design Institue Co., Ltd., 68 Shaoshan Road, Changsha 410075, China
通讯机构：
[Peng Liu] N;National Engineering Research Center for High Speed Railway Construction, Changsha 410075, China<&wdkj&>China Railway Group Ltd., 69 Fuxing Road, Beijing 100039, China<&wdkj&>China Railway No. 10 Engineering Group Co., Ltd., 2000 Shunhua Road, Jinan 250101, China<&wdkj&>School of Civil Engineering, Central South University, 22 Shaoshan Road, Changsha 410075, China<&wdkj&>Author to whom correspondence should be addressed.
关键词：
super-long mass concrete;temperature field;strain;thermal stress;shrinkage-compensating concrete;numerical simulation
摘要：
In this study, the combination of ordinary cement concrete (OCC) and shrinkage-compensating concrete (SCC) was utilized to pour super-long mass concrete. The temperature and strain of the concrete were continuously monitored and managed actively after pouring. The investigation focused on the temporal and spatial distribution patterns of the temperature field, the temperature difference between the core and surface, and the strain evolution. Based on the constructed hydration exothermic model of layered poured concrete, the effects of the SCC, molding temperature, and surface heat transfer coefficient on the temperature field were analyzed. The results show that the temperature of super-long mass concrete rises quickly but falls slowly. SCC exhibits higher total hydration heat than OCC. The temperature field is symmetric along the length but asymmetric along the thickness due to varying efficiency of heat dissipation between the upper and lower parts of the concrete. After final setting of the concrete, the strain varies opposite to the temperature and peaks at −278 με. A few short cracks are observed on the end of the upper surface. Moreover, the numerical simulation results are in good agreement with the measured results. Increasing the molding temperature and surface wind speed increases the temperature difference between the core and surface. Conversely, increasing the thickness of the insulation layer is an effective way to curtail this difference. Thermal stress analysis is carried out and shows that lowering the molding temperature of SCC and increasing the thickness of insulation material can effectively reduce thermal stress.
摘要：
The salt gradient solar pond (SGSP) is a low-cost and large-scale solar energy capture and storage device. The stability of the non-convective zone (NCZ) is critical for the well-functioning and efficiency of SGSP. To understand when and how SGSP lost its effectiveness, the turbulent double-diffusive convection in solar ponds was first solved numerically with a Large Eddy Simulations (LES) model. The simulations show that attaching a porous layer or increasing the initial salt concentration effectively delays the destruction of NCZ. By increasing the initial salt concentration from 5.2% to 20.8%, the destruction time increases from 7 to 22 h. By attaching a porous layer, the overturn time can increase by about 8 h, resulting in a temperature rise from 46 C-o to 73 C-o in the storage layer. The flow field analysis shows that both interface erosion and turbulent mixing in NCZ cause the destruction of NCZ. The stability analysis shows that the turbulent mixing decreases the salinity gradient in NCZ, making it more susceptible to erosion. By inhibiting the turbulent mixing, the porous layer at the bottom can effectively delay the arrival of NCZ destruction. Thus, the heat storage capacity and stability of solar ponds are enhanced.
