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Test Method and Influencing Factors of Fluidity of Synchronous Grouting Material in Shield Tunnel Construction

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Zhongguo Tiedao Kexue/China railway Science 2022年第3期43卷 94-102页

作者： Huang, Dawei Luo, Zhongrui Luo, Wenjun Xu, Changjie Shi, Haibin Zhang, Li Engineering Research Center of Railway Environmental Vibration and Noise Ministry of Education East China Jiaotong University Nanchang330013 China State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong University Nanchang330013 China Department of Railway Engineering Tianjin Railway Technical and Vocational College Tianjin300240 China

In the construction of existing shield tunnel, the fluidity of synchronous grouting material is usually tested by consistency systems or gauges. However, the interference of manual operation as well as the randomness of the test have great impact on the test results. Moreover, the sinking depth of the test cone is not directly related to the flow resistance of slurry in the grouting pipe. Therefore, a set of fluidity test devices for synchronous grouting material is developed, which can directly measure the pressure loss of slurry in the grouting pipe. The pressure loss per unit length of the grouting material in the grouting pipe is proposed as the evaluation index of the grouting material fluidity, and the ratio of the surface area of the aggregate particles in the grouting material to the volume of the slurry (surface-to-volume ratio) is taken as the influencing parameter to analyze the grouting material fluidity. The calculation formula for the ratio of superficial area to volume is deduced. The developed fluidity test device is used to test and compare the fluidity of synchronous grouting materials used on site and grouting material samples prepared indoors with different surface-to-volume ratios. The results show that the developed fluidity test device for synchronous grouting material is feasible. The surface-to-volume ratio of grouting material is the main influencing parameter of its fluidity. The pressure loss per unit length of grouting material in the grouting pipe approximately linearly increases with the increase of the initial pressure. The pressure loss per unit length of grouting material in the grouting pipe and the initial pressure suggest an approximately linear relationship. The content of aggregate (solid particles with particle size greater than 0. 075 mm) in the grouting material is higher, that is, the larger the surface-to-volume ratio, the higher the pressure loss per unit length in the grouting pipe. © 2022, Editorial Department of China

关键词： Mortar

Collaborative passenger flow control on an oversaturated metro line: a path choice approach

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Transportmetrica B 2020年第1期8卷 376-404页

作者： Meng, Fanting Yang, Lixing Wei, Yun Li, Shukai Gao, Ziyou Shi, Jungang State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China National Engineering Laboratory for Green & Safe Construction Technology in Urban Rail Transit Beijing China College of Transportation and Logistics East China Jiaotong University Nanchang China Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety Tongji University Shanghai China

Focusing on reducing the traffic congestion on an oversaturated urban metro system, this study investigates the collaborative passenger flow control problem for a metro line. By introducing the timetable-oriented space-time network representation, the problem of interest is finally formulated as an integer programming model, in which the objective function aims to minimize the total weighted passenger waiting time at different stations. Since the final decision is closely related to the space-time path-finding process, the proposed model can also be regarded as a coordinated path-finding process with train loading capacity constraints. Then, an efficient heuristic algorithm is developed to solve the proposed model. Finally, a series of numerical examples are implemented on a sample metro line and the Beijing Batong metro line. The computational results show that the proposed approach can produce high-quality passenger flow control strategies for the metro system, thereby demonstrating the effectiveness of the proposed model and algorithm. © 2020, © 2020 Hong Kong Society for Transportation Studies Limited.

关键词： Collaborative passenger control integer programming model lagrangian relaxation approach space-time network

Study on the bearing characteristics of rapid curing pile formation on beach foundation

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Study on the bearing characteristics of rapid curing pile fo...

2nd International Conference on Power, Communication, Computing and Networking Technologies (PCCNT 2024)

作者： Chun Li Jiayu Qian Bing Zhang Jingwei Liu Jinan Rail Transit Group Construction Investment Co. Ltd. Jinan 250014 People's Republic of China State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering China University of Mining and Technology Xuzhou 221116 People's Republic of China Jinan Liwen Geotechnical Engineering Co. Ltd. Jinan 250061 People's Republic of China

ISBN: (数字)9781837242405

The reinforcement of soft sandy soil foundation is not only the important problem of fast consolidation facility project security, but also an important measure related to the safety of civil engineering. Through field tests, the ultimate bearing characteristics of monopiles formed by rapid consolidation using curing agent were studied under different working conditions. By designing six different length-to-diameter ratio of the monopile working conditions for vertical and water calm load test. The test results indicate that the ultimate vertical bearing capacity of monopiles under six working conditions ranges from 7-54 kN. The vertical bearing capacity of monopiles increases as the pile diameter and length increase. However, increasing the pile length will lead to higher ultimate bearing capacity, but also results in increased settlement at the pile top, which fails to meet the design's displacement requirements. To address this, it is necessary to increase the pile diameter to improve lateral friction resistance and reduce settlement displacement. Additionally, the horizontal ultimate bearing capacity of a single pile increases with the length of the pile. For a pile diameter of 10 cm, the ultimate bearing capacity for pile lengths of 0.5m and 1m are 0.975 kN and 1.4 kN respectively, with the bearing capacity primarily influenced by the pile's strength. The pile did not fracture when the pile diameter was increased to 30cm and the pile length was 0.5m. The ultimate bearing capacity of bearing platform with infill pile is 400kN, which is 23.1% higher than that without infill pile, so the bottom infill pile can obviously improve the ultimate bearing capacity of foundation.

关键词：

Minimum Effective Loosening Resistance Torque as a Way to Optimal Trade-Off between Anti-Loosening Performance and Fatigue Life

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SSRN 2023年

作者： Liu, Xi Abid, Salim Yang, Long Yang, Ce Shchelkanova, Evgeniia School of Mechanical Engineering Yanshan University No. 438 West Hebei Avenue Hebei Qinhuangdao066004 China State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong University Chengdu610031 China Omsk Oblast Omsk 2d Barnaulskaya Street 12-53 644001 Russia

The study introduces a novel parameter for the frictional fasteners assessment and optimization of minimum effective loosening resistance torque (TuR-min). TuR-min is the minimum value of the thread friction torque, which is sufficient for loosening prevention yet small enough to spare the fatigue life. Its mechanism and estimation approach using conventional methods are described in detail. We also propose an affordable and sophisticated TuR-min measurement method. Additionally, using TuR-min measurements in M12 and M16 fasteners we deduced an equation for TuR-min estimation in any fastener size. The equation eliminates the need for laborious analytical and experimental procedures. The study results can be employed in upcoming structural designs of anti-loosening threaded fasteners, as well as for the available fasteners assessment. © 2023, The Authors. All rights reserved.

关键词： Finite element method

Iterative Solution and Numerical Analysis of Vehicle-Track-Bridge Nonlinear Coupled Vibration Considering the Viscoelasticity of Fasteners

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SSRN 2023年

作者： Cui, Weitao Gao, Liang Liu, Linya Miao, Shuaijie Niu, Zhenyu Xiao, Yixiong School of Civil Engineering Beijing Jiaotong University Beijing100044 China Frontiers Science Center for Smart High-speed Railway System Beijing Jiaotong University Beijing100044 China State Key Laboratory of Performance Monitoring Protecting of Rail Transit Infrastructure East China Jiaotong University Nanchang330013 China

To investigate the effect of fastener viscoelasticity on vibrations of the vehicle, track, and bridge, we propose a vehicle-track-bridge nonlinear coupled model in the time domain considering fastener viscoelasticity based on the finite element method (FEM). This model represents fasteners using the fraction Voigt and Maxwell mode in parallel (FVMP) model and applied to the track-bridge element. The dynamic equations for the track-bridge element model with fractional derivatives are derived based on the Lagrange equation. To improve the computational efficiency of the time-domain model with fractional derivatives, a cross-iteration algorithm incorporating a relaxation factor is employed to solve the dynamic responses of the coupled system. The conclusions demonstrate that the FVMP model can effectively represent the viscoelastic properties of rail pads over a wide range of temperatures and frequencies. The nonlinear model can converge with larger time steps, improving convergence speed and iteration stability by using the cross-iteration algorithm and introducing a relaxation factor to correct wheel-rail forces. The relaxation factor in the range of 0.3-0.5 demonstrates favorable convergence effects. Fastener viscoelasticity significantly affects high-frequency vibrations in the coupled system, particularly in the wheel-rail coupling resonance range. It is recommended to consider the viscoelasticity of fasteners when making precise predictions for track structure vibration and noise. © 2023, The Authors. All rights reserved.

关键词： Equations of motion

Modeling of Energy Consumption Influencing Factors of Urban rail transit Station based on System Dynamics 4

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Modeling of Energy Consumption Influencing Factors of Urban ...

2020 4th International Conference on Traffic engineering and Transportation System, ICTETS 2020

作者： Zhang, Chenchen Wang, Yanhui Xiao, Xuemei Luo, Zhiwei School of Mechanical and Automotive Engineering Xiamen University of Technology Xiamen China State Key Laboratory of Rail Transit Control and Safety Beijing Jiaotong University Beijing China

The energy consumption of urban rail transit station is an important part of the total energy consumption. In this paper, we focus on the energy consumption of urban rail transit stations. After analyzing the influencing factors and their relationship of station energy consumption from the aspects of electromechanical equipment and operation level, we establish the causal loop diagram of the influencing factors of station energy consumption based on system dynamics, and construct the system dynamics model of station energy consumption. Through simulation calculation, the effects of various influencing factors on the total energy consumption of the station are obtained. Moreover the key factors affecting station energy consumption are found. At last, the concrete measures to improve the energy consumption and energy saving efficiency of the station are presented, which provides theoretical support for the optimization of energy saving of the urban rail transit system. © Published under licence by IOP Publishing Ltd.

关键词： Energy utilization

Numerical Tests on Dynamic Response of Embankment with Pile-Supported Foundation for High-Speed railway in Soft Ground Using Soil-Water Coupling Elastoplastic Fem

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SSRN 2024年

作者： Huang, Qiang Zhu, Wenxuan Iwai, Hiromasa Wu, Yuqi Zhang, Shiping Zhang, Feng School of Civil & Environmental Engineering and Geography Science Ningbo University Ningbo China Innovation Center of Coastal Urban Rail Transit Ningbo University Ningbo China State Key Laboratory of Ocean Engineering Department of Civil Engineering Shanghai Jiao Tong University Shanghai China Department of Urban Management Kyoto University Kyoto Japan National Engineering Research Center of Highway Maintenance Technology Changsha University of Science & Technology Hunan Changsha410114 China Department of Geotechnical Engineering Tongji University Shanghai China

Embankment with pile-supported foundation (PSF) is widely used for high-speed railway (HSR) built in soft ground due to its efficient construction, low cost and good performance for settlement control. The effectiveness of PSF in reducing high-speed train induced vibration has been extensively studied by numerical simulation. However, the dynamic analyses are usually performed with elastic or viscoelastic models without considering the nonlinearity and soil-water coupling in soft ground. In this paper, 2D soil-water coupling elastoplastic FEM was adopted to investigate the influence of PSF and response discrepancies among different types of PSF for HSR, namely pile-net, pile-plate, pile-raft foundations. Vertical dynamic stress, excess pore water pressure (EPWP), acceleration and displacement of the embankment and subsoil were numerically analyzed in detail. The results show that PSF is very effective to reduce the peak accelerations, displacements as well as EPWP in soft ground, but also induces significant stress fluctuations in the embankment and stronger dynamic responses beneath the pile tips compared to the unreinforced ground. The vertical acceleration and EPWP from PSF are partitioned sharply by the piles, significant fluctuations occur along the horizontal direction while vertical displacement along depth direction becomes more uniform within the pile-reinforced area. Different type of PSF has important influence on the acceleration and EPWP responses in soft ground that the larger stiffness of PSF is, the less peak acceleration and EPWP may be. However, the displacement responses among different PSF are almost similar since the displacement is basically controlled by the piles rather than the pile cap or raft. © 2024, The Authors. All rights reserved.

关键词： Piles

A Novel Feature Optimization And Ensemble Learning Method For state-of-Health Prediction Of Mining Lithium-Ion Batteries

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SSRN 2024年

作者： Feng, Juqiang Cai, Feng Zhao, Yang Zhang, Xing Zhan, Xinyu Wang, Shunli State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and Technology Huainan232000 China Rail Transit Power Supply and Control Engineering Technology Research Center Huainan Normal University Huainan232038 China Wuhu Tianyi energy Technology Co. LTD Wuhu241000 China School of Information Engineering Southwest University of Science and Technology Mianyang621000 China

In this work, accelerated aging tests at different temperatures are conducted for 228Ah mining lithium-ion batteries, and a SOH prediction method with health features (HFs) optimization and ensemble learning method is proposed. Firstly, six health features are extracted from cyclic charge/discharge data. Simultaneously, to solve the problem of a single feature not fully reflecting the SOH at multiple temperatures, canonical correlation analysis is introduced to construct the feature fusion vector to obtain the comprehensive health feature (C-HF). Secondly, the complementary ensemble empirical mode decomposition method is used to smooth the features and the SOH of the battery to extract the raw data of the battery to be tested in the stable frequency range. Then, four different datasets are used to comprehensively evaluate the performance of C-HF in the ensemble learning method. Compared with other HFs, the optimized feature C-HF has the best SOH prediction in all datasets, with high prediction accuracy and strong robustness. Finally, we compare SVM, CNN, and LSTM-SVM with the proposed method in this paper for SOH prediction. Regardless of whether 30% or 70% of training datasets are used, the proposed method's estimation results are closer to the actual in SOH. © 2024, The Authors. All rights reserved.

关键词： Forecasting

Seepage Propagation Simulation of a Tunnel Gasketed Joint Using the Cohesive Zone Model

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SSRN 2023年

作者： Gong, Chenjie Cheng, Mingjin Peng, Yicheng Ding, Wenqi Ge, Yangyang Song, Jianrong School of Civil Engineering Hunan Provincial Key Laboratory for Disaster Prevention and Mitigation of Rail Transit Engineering Structure Central South University HN Changsha410075 China School of Civil Engineering Central South University HN Changsha410075 China Shanghai Electric Power Design Institute SH Shanghai200025 China Department of Geotechnical Engineering Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education College of Civil Engineering Tongji University SH Shanghai200092 China State Key Laboratory of Special Functional Waterproof Materials Beijing Oriental Yuhong Waterproof Technology Co. Ltd. Beijing101309 China

The gasketed joint plays a critical role in the waterproof or water-leakage resistance performance of tunnel segmental linings. This study presents a novel numerical simulation method based on the cohesive zone model (CZM) to accurately analyze the seepage phenomena along the interface of elastic sealing gaskets in shield tunnel joints. While traditional finite element methods are widely used, they cannot simulate interface opening, limiting their applicability. To overcome this challenge, the proposed method leverages the concept of hydraulic fracturing and redefines the seepage problem as a seepage problem of elastic impermeable media. By establishing a two-dimensional hydraulic fracturing model using the CZM, this study conducts a comprehensive sensitivity analysis of the cohesive element parameters and validates the accuracy and effectiveness of simulating seepage along the interface of elastic impermeable media. Based on the insights gained from the sensitivity analysis, a seepage calculation model is successfully developed, considering the unique characteristics of elastic sealing gaskets. The model is applied to three cross-sectional shapes of elastic sealing gaskets, and their seepage characteristics are analyzed based on the interface opening displacement and liquid pressure distributions during seepage. The results highlight the SC4 cross-sectional shape, which exhibits minimal opening displacement and the highest net water pressure at the moment of seepage occurrence, demonstrating superior waterproof performance compared to other forms. Through the introduction of the CZM, comprehensive parameter analysis, validation, and practical application, this study overcomes the limitations of traditional finite element methods in simulating interface opening. The proposed model, which more accurately captures seepage characteristics than other methods, provides an optimized simulation method for analyzing hydraulic coupling issues related to seepage at shield tun

关键词： Sensitivity analysis