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SSRN 2023年

作者： Liang, Ximei Fei, Hua Li, Yuanlin Li, Peisheng Du, Wenqing Zhou, Jiahong Jiangxi Province Key Laboratory of Environmental Geotechnical Engineering and Hazards Control Jiangxi University of Science and Technology Jiangxi Province Ganzhou341000 China Energy and Power Engineering Nanchang Institute of Technology Nanchang330000 China

In this work, a ternary phase change material (PCM) was manufactured by mixing capric acid-stearic acid (CA-SA) and paraffin (PW) and packaged and shaped with expanded graphite (EG) as a carrier. The CA-SA-PW/EG material cement mortar was prepared by direct stirring, and its thermal conductivity, thermal stability, and heat storage properties were investigated. When the PCM content reaches 15% (PCM-4), the thermal conductivity of the composite phase change cement plate is 1.566 W/(m·K). During the static heat storage, the PCM-4 cement plate showed evident thermal stagnation, reduced by 4.7 ℃. In the light heat storage, when the heating surface of each cement plate reaches 55 ℃, the temperature difference between the heating surface and the light surface of PCM-4 is 23.11 ℃. The heating surface drops to 16.5 ℃, PCM-4 cement plate takes 3500s, delaying the temperature change effectively. The maximum temperature difference between the inner and outer surface of PCM-4 is 14.039 ℃ in the microchamber temperature control characteristics with 400 W heating, which is 62.5% larger than the ordinary cement plate. Moreover, the temperature damping of the cement plate reaches 1.30 in the range of 22-32 ℃. © 2023, The Authors. All rights reserved.

关键词： Phase change materials

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Numerical analysis of the effect of pre-precipitation of foundation pits on adjacent group piles 4

Numerical analysis of the effect of pre-precipitation of fou...

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4th International Symposium on Traffic Transportation and Civil Architecture, ISTTCA 2021

作者： Huang, Zhan-Jun Li, Yi-Xian Peng, Jun-Ren Zeng, Yun-Rong Wang, An-Hua Xu, Chang-Jie Nanchang Railway Transportation Group Co Ltd Nanchang330038 China Nanchang Railway Transportation Group Engineering Technology Consulting Co China Key Laboratory of Geotechnical Engineering Infrastructure Safety and Control In Jiangxi Province East China Jiaotong University Jiangxi Nanchang330013 China

ISBN: (纸本)9781665425926

Pre-precipitation before excavation of the foundation pit will cause the displacement of the surrounding soil, which will affect the adjacent group piles in turn. Based on the foundation pit engineering of a station in Nanchang Metro Line 4, this paper establishes a three-dimensional fluid-solid coupling model of the influence of pre-dewatering on adjacent group piles with the help of PLAXIS 3D finite element software, studies the settlement pattern of the ground surface outside the pit and the mechanism of force deformation of the adjacent piles under the pre-dewatering condition, and further analyzes the influence of the pile length and pile diameter on the stress and deformation of the pile foundation. The calculation results show that the vertical displacement distribution of the surface outside the pit caused by precipitation is 'spoon-shaped', and the existence of the adjacent piles will hinder the displacement of the surrounding soil. The vertical displacement of the pile foundation gradually decreases with the increase of the pile depth and distance from the pit. When controlled variables are used, the increase in pile length and pile diameter leads to an increase in the ability to resist the surrounding soil displacement and a decrease in vertical displacement. Especially as pile diameter increases, the range of variation in vertical displacement of the pile foundation decreases significantly. The maximum axial force of the pile foundation tends to increase with the pile length or pile diameter increasing, and the position of the neutral point also moves downward due to its influence. © 2021 IEEE.

关键词： Piles

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Numerical analysis of the influence of pre-submergence of foundation pits on adjacent existing tunnels 4

Numerical analysis of the influence of pre-submergence of fo...

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4th International Symposium on Traffic Transportation and Civil Architecture, ISTTCA 2021

作者： Xu, Ming Xia, Xue-Qin Liang, Xin-Huan He, Xiao-Hui Xu, Chang-Jie Jiang, Ya-Long Nanchang Railway Transportation Group Co. Ltd Jiangxi Nanchang330038 China Nanchang Railway Group Engineering and Technology Consulting Co Ltd Jiangxi Nanchang330038 China Key Laboratory of Geotechnical Engineering Infrastructure Safety and Control In Jiangxi Province East China Jiaotong University Jiangxi Nanchang330013 China

ISBN: (纸本)9781665425926

Construction such as foundation pit precipitation and excavation can lead to redistribution of stresses in the soil, which can affect the adjacent existing tunnel and even cause cracking of the existing tunnel. Using a foundation pit in Nanchang as a case study, a numerical model was established using PLAXIS 3D software to investigate the effect of pre-submergence of the foundation pit on the adjacent existing tunnel, and the influence of factors such as the burial depth of the existing tunnel and the distance d between the tunnel and the foundation pit on the tunnel deformation was discussed. The results of the study show that as the depth of the tunnel increases, the tunnel deforms in the direction of the pit, with the bending moment, horizontal and vertical displacement of the tunnel being 'large in the middle and small at the ends', and the maximum value of the displacement decreases gradually, while the maximum value of the bending moment. In addition, when the burial depth is less than 1.0H, the influence of the spacing d is the greatest, the larger the spacing d the smaller the displacement value of the tunnel;while when the burial depth is greater than 1.0H, the burial depth becomes the main factor affecting the tunnel deformation. © 2021 IEEE.

关键词： Bending moments

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Review on Research Progress of MICP Technology

Review on Research Progress of MICP Technology

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2021 International Conference on Advanced Technologies and Applications of Modern Industry, ATAMI 2021

作者： Cui, Meng Xiong, Huihui Lü, Suying College of Civil and Structure Engineering Nanchang Institute of Technology Nanchang330099 China Jiangxi Provincial Engineering Research Center Special Reinforcement and Safety Monitoring Technology in Hydraulic and Civil Engineering Nanchang330099 China Jiangxi Province Key Laboratory of Hydraulic and Civil Engineering Infrastructure Security Nanchang330099 China

MICP technology is a new technology proposed for soil reinforcement research in recent years, which has the advantages of environmental protection and sustainability. Through the review and analysis of domestic and foreign literature, the mechanism of microbial mineralization reaction and the research progress of domestic and foreign scholars were comprehensively summarized. This paper introduces the basic principle of urea hydrolysis in MICP technology, and expounds the control factors of microbial mineralization experiment and the practical application of this technology in engineering. Finally, the future development prospect of MICP technology is forecasted. © Published under licence by IOP Publishing Ltd.

关键词： Sustainable development

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Adaptive Backstepping Sliding Mode control of High-speed Train Based on Fuzzy Regulation 5

Adaptive Backstepping Sliding Mode Control of High-speed Tra...

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5th International Conference on Industrial Artificial Intelligence, IAI 2023

作者： Fu, Yating Tian, Junhao Yang, Hui East China Jiaotong University State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure Nanchang330013 China East China Jiaotong University Key Laboratory of Advanced Control and Optimization of Jiangxi Province Nanchang330013 China East China Jiaotong University School of Electrical and Automation Engineering Nanchang330013 China East China Jiaotong University Nanchang330013 China

ISBN: (纸本)9798350325294

In order to meet the operational requirements of the high-speed train in terms of safety, accuracy and smoothness, an adaptive backstepping sliding mode control approach based on fuzzy regulation is put forward in this paper. Firstly, to solve the problem of insufficient accuracy of the single point model, this paper establishes a mass point dynamics model of the high-speed train and sets a compensation term for the model considering the uncertainties in the operation process. Secondly, the adaptive law is designed to estimate the compensation term and the new backstepping sliding mode control strategy is developed. Finally, fuzzy rules are designed to adjust the switching gain of the sliding mode term to suppress jitter. The results of simulation and comparison experiments demonstrate the effectiveness and feasibility of the proposed modeling and control method. © 2023 IEEE.

关键词： Railroads

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Tracking control of High-Speed Trains Based on An Improve Disturbance Observer

Tracking Control of High-Speed Trains Based on An Improve Di...

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Data Driven control and Learning Systems (DDCLS)

作者： Jian-Ping Zhang Lin-Bao Deng Chun-Hua Xie School of Electrical and Automation Engineering East China Jiaotong University Nanchang Jiangxi China State Key Laboratory of Performance Monitoring Protecting of Rail Transit Infrastructure East China Jiaotong University Nanchang Jiangxi China Key Laboratory of Advanced Control & Optimization of Jiangxi Province Nanchang Jiangxi China

Accurate tracking of position and velocity is a critical problem to be solved for the automatic train operation (ATO) system. However, achieving automatic operation for high-speed trains (HSTs) is difficult due to unknown disturbances and actuator faults. This paper uses an improved disturbance observer-based control (IDOBC) strategy to solve this issue. Each carriage is considered a particle and connected by a flexible coupler to establish the multiple point-mass model for HSTs by considering unknown lumped disturbances and actuator faults. For the lumped disturbances caused by the external environment, an improved disturbance observer is designed to compensate for the impact caused by this component on HSTs. Based on the given linear matrix inequality, the HSTs system satisfies the $H_{\infty}$ performance under the IDOBC strategy. Compared with traditional DOBC, the proposed IDOBC has higher tracking accuracy.

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The Research of Dynamics Property and Long-Term Settlement About Weathered Argillaceous Siltstone Under Base of Subway Tunnel 1

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6th GeoChina International Conference on Civil and Transportation infrastructures: From engineering to Smart and Green Life Cycle Solutions, GeoChina 2021

作者： Shi, Yu-Feng Yu, Chao Chen, Xiang-Sheng Zhao, Xiu-Shao Zhu, Bi-Tang National Experimental Teaching Demonstration Center of Civil Engineering East China Jiaotong University Jiangxi Nanchang330013 China Jiangxi Key Laboratory of Infrastructure Safety Control in Geotechnical Engineering Nanchang330013 China Foshan Railway Investment and Construction Group Co. Ltd. Foshan52800 China

ISBN: (数字)9783030803162

ISBN: (纸本)9783030803155

Subway tunnel of Nanchang may pass through one or several weathered argillaceous siltstone in the construction process. To reveal the influence of weathered argillaceous siltstone on the long-term settlement of subway tunnel, the dynamic triaxial tests of intensely and moderately weathered argillaceous siltstone were carried out. Based on these tests results, the evolution law of cumulative plastic dynamic strain was analyzed and a prediction model of cumulative plastic strain was established. Finally, an actual subway tunnel with weathered argillaceous siltstone was selected for long-term settlement prediction analysis. The prediction data shows that the sedimentation value of tunnel is approximately 20.87 mm under 100 years operation. Research results indicate that the dynamic strain of weathered argillaceous siltstone under cyclic vibration load is mainly affected by dynamic stress and static deviatoric stress. When the static deviatoric stress increased from 0 kPa to 200 kPa, the dynamic strain of intensely and moderately weathered argillaceous siltstone increased by 8.53 times and 5.97 times, respectively. Therefore, the intensely weathered argillaceous siltstone (IWAS) is more susceptible to static deviatoric stress than moderately weathered argillaceous siltstone (MWAS). In addition, increasing the confining pressure will accelerate the expansion of fissures in intensely weathered argillaceous siltstone, while the fissures in moderately weathered argillaceous siltstone will be inhibited, which show diametrically opposite results. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Stresses

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Quantitative Evaluation on the Effects of the Spatial Variability in Concrete Materials on Seismic Damage of Concrete Gravity Dams

SSRN

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SSRN 2024年

作者： Wei, Qingyang Shen, Lei Dunai, László Kövesdi, Balázs Elqudah, Sara Cao, Maosen College of Mechanics and Materials Hohai University Nanjing China Department of Structural Engineering Budapest University of Technology and Economics Budapest Hungary College of Water Conservancy and Hydropower Engineering Hohai University Nanjing China Jiangxi Province Key Laboratory of Environmental Geotechnical Engineering and Hazards Control Jiangxi University of Science and Technology Ganzhou China

The influencing mechanism of spatial variability in concrete materials on the seismic damage of concrete gravity dams is still unclear, and existing methods for evaluating the seismic damage are insufficient. In this work, the effects of concrete’s spatial variability on the seismic damage distribution, energy dissipation, and deformation in concrete gravity dams are performed based on the damaged plastic model of concrete. Prior to the seismic damage analysis, the method for seismic inputting and the correlation function for realizing random fields of concrete materials are carefully determined. Based on the seismic damage analysis of the Koyna gravity dam, the tensile strength has the greatest influence on the seismic damage, followed by the elastic modulus. Aiming at the tensile strength parameter, the decrease of correlation distance and the increase of coefficient of variation increase the seismic damage degree and complicate the damage distribution. A convenient and comprehensive damage profiling indicator is proposed, so that can avoid the one-sidedness and evaluation error caused by using a single scalar damage value. The triangular area enclosed by the various damage indexes represents the comprehensive damage degree, and the shape change of the damage triangle indicates the change in the damage pattern of the dam. This damage profiling indicator is specifically designed to quantitatively distinguish and evaluate the damage degrees between a series of damage cases. © 2024, The Authors. All rights reserved.

关键词： Gravity dams

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Application of Water Quality Index in the Evaluation of an Abandoned Mine Areas of Xunwu, China

Application of Water Quality Index in the Evaluation of an A...

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2020 International Conference on Innovative Solutions in Hydropower and Environmental and Civil engineering

作者： Yin, Shiyun Liu, Zuwen Yang, Shi Lin, Yuan Jiangxi Key Laboratory of Environmental Geotechnical and Engineering Disaster Control Ganzhou341000 China Engineering Technology Research Center for Water Quality Safety Assurance of Ganjiang River Basin Jiangxi University of Science and Technology Ganzhou341000 China

Within the display think about, an surrendered ion-type rare soil mine contains a tremendous affect on the encompassing water environment contamination in Xunwu, jiangxi province, China. Since the usage of coordinates remediation innovation and extend in 2018, its natural quality has been enormously moved forward. In arrange to encourage assess the environmental remediation impact, a altered water quality index strategy (WQI) is proposed. Concurring to the grid method, 16 water quality examining focuses were set within the surrendered mine remediation extend, and 9 key assessment records such as NH4+-N and heavy metals were chosen for principal component analysis (PCA) and factor analysis (FA), in arrange to comprehensively assess the worldly and spatial changes of different contamination variables within the deserted mine environmental remediation range. The results uncovered that the water quality of the surface water has been slowly progressed, and the generally water quality has been getting superior, among which the water quality in August is clearly superior than that in July, and the progressed water quality index is successful for the classification of water quality and the assessment of the transient and spatial changes of water quality within the remediation of surrendered mines. © Published under licence by IOP Publishing Ltd.

关键词： Water quality

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Adaptive Backstepping Sliding Mode control of High-speed Train Based on Fuzzy Regulation

Adaptive Backstepping Sliding Mode Control of High-speed Tra...

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International Conference on Industrial Artificial Intelligence (IAI)

作者： Yating Fu Junhao Tian Hui Yang State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong University Nanchang China Key Laboratory of Advanced Control and Optimization of Jiangxi Province East China Jiaotong University Nanchang China School of Electrical and Automation Engineering East China Jiaotong University Nanchang China

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