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Simulation of the Influence of Ultra-deep Foundation on Groundwater Seepage Field Based on Unsaturated Flow

Simulation of the Influence of Ultra-deep Foundation on Grou...

Hydraulic and Civil engineering & Smart Water Conservancy and Intelligent Disaster Reduction Forum (ICHCE & SWIDR), International Conference on

作者： Xiaoqing Song Hongwu Lei Fuhua Fei Zhendong Cao Qin Peng Xiuchao Pu Ying Wang School of Environmental Studies China University of Geosciences Wuhan China 111 Geological Party Guizhou Bureau of Geology and Mineral Exploration & Development Guiyang China Geo-engineering investigation institute Guiyang guizhou China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan China Guiyang Rail Transit Line 3 Phase I Project Construction Management Co. Ltd Guiyang China

ISBN: (纸本)9781665465540

The anti-floating water level of ultra-deep foundation is affected not only by the geological conditions of water level, but also by the foundation itself. In this paper, unsaturated seepage numerical simulation is used to evaluate the influence of typical ultra-deep foundation on groundwater seepage field in Guiyang. The results show that the construction of the foundation blocks the flow of groundwater, resulting in changes in the local seepage field. The water level in the upstream of the foundation rises, while it in the downstream of the foundation decreases. The maximum rise of the water level exceeds 1 m, while the maximum decrease exceeds 0.4 m. The time of foundation influence on seepage is up to 3 years, and the first 120 days are the great influence period. The pattern of water level change is controlled by the shape of the foundation plane. Sensitivity analysis shows that permeability and hydraulic gradient have important influence on the results. Therefore, when evaluating the anti-floating water level of foundation, not only the dynamic characteristics of groundwater itself, but also the impact of foundation construction should be considered.

关键词： Water Shape Sensitivity analysis Simulation Geology Hydraulic systems Numerical simulation

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A modified J-C constitutive model and novel strain rate-dependent fracture criterion for A7N01S-T5 under different loading

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International Journal of Impact engineering 2025年 206卷

作者： Haoxu Ding Tao Zhu Wenyue Yuan Jinle Wang Xiaorui Wang Bing Yang Shoune Xiao State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong University Chengdu 610031 China R&D Center CRRC Qingdao Sifang Co. Ltd. Qingdao 266000 China School of Mechatronic Engineering Changchun University of Technology Changchun 130012 China

To study the dynamic and static mechanics and fracture characteristics of A7N01S-T5 aluminum alloy in detail, the related research was carried out based on the combination of experiment and simulation. Firstly, the dynamic and static mechanical performance tests under several stress states were carried out, and the stress state parameters and equivalent fracture strain of different tests were obtained based on the finite element reverse engineering method. On this basis, the Von Mises yield function and Lou2022 yield function are used to describe the yield and hardening characteristics of the material under quasi-static conditions, and the DF2016 criterion is used to describe the quasi-static fracture characteristics. Then, the classical and modified J-C constitutive models are used to describe the material's dynamic yield and hardening characteristics. Finally, a new strain rate-dependent fracture criterion is proposed to describe the dynamic fracture characteristics of the material. The results show that the material's mechanical properties are related to the stress state and strain rate. The dynamic and static mechanical properties of A7N01S-T5 aluminum alloy can be well described by the Lou2022 yield function and modified J-C constitutive model. The newly constructed strain rate-dependent fracture criterion can characterize the difference in the influence of strain rate on fracture characteristics under different stress states, and the prediction accuracy is significantly improved compared with the traditional J-C fracture criterion.

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Three-dimensional train-periodic slab track-subgrade dynamics model based on the iterative solution and Green's function method

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Computers and Structures 2025年 315卷

作者： Sun, Yu Zhang, Sen Xing, Mengting Shi, Zhiyong Liu, Pengfei College of Transportation Engineering Nanjing Tech University Nanjing210009 China Key Laboratory of Mechanical Behavior Evolution and Control of Traffic Engineering Structures in Hebei Shijiazhuang Tiedao University Shijiazhuang050043 China College of Rail Transit Wuxi University Wuxi214105 China Department of Industrial Engineering University of Florence Florence50139 Italy State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China

This paper develops an iterative solution model for the efficient and accurate simulation of the dynamics of a three-dimensional (3D) train-periodic slab track-subgrade (TPSTS) system. The entire system is divided into the train-rail subsystem and the periodic slab-subgrade subsystem. An ordinary differential equation (ODE) model of the train-rail system is established, and a step-moving strategy is employed to enhance the computational efficiency. A frequency-domain Green's function method (GFM) model is employed for modelling the periodic slab-subgrade. Considering the periodicity, symmetry, and attenuation characteristics of the track structure, the Green's function of the slab-subgrade structure is obtained by conducting harmonic response analysis on a finite element model (FEM) of a quarter slab-subgrade structure. The proposed model is utilized to investigate the vibration characteristics of the high-speed train-track-subgrade system. The results indicate that the model exhibits good convergence, accuracy, and efficiency. The periodicity of the track structure has a significant impact on the statistical values of subgrade displacement and stress amplitudes along the track's longitudinal direction. At the subgrade surface, the amplitudes of displacement, stress, and acceleration exhibit fluctuations in the lateral direction of the track. However, with increasing depth, these amplitudes generally attenuate, leading to a more uniform distribution. © 2025 Elsevier Ltd

关键词： railroad transportation

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Analysis for Rank Distribution of BATS Codes under Time-Variant Channels

Analysis for Rank Distribution of BATS Codes under Time-Vari...

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IEEE Conference on Vehicular Technology (VTC)

作者： Lin Tang Heng Liu Liu Yang Zheng Ma Ming Xiao State Key Laboratory of Rail Transit Engineering Informatization(FSDI) Xian Shanxi P.R.China Key Lab of Information Coding & Transmission Institude of Mobile Communication Southwest Jiaotong University Chengdu Sichuan P.R.China KTH Royal Institute of Technology Stockholm Sweden

ISBN: (数字)9781728152073

ISBN: (纸本)9781728140537

A batched sparse (BATS) code provides a novel two-stage coding structure for the multi-hop network, in which the outer code performed at the source node generates a potentially unlimited number of batches and the inner code at the intermediate network nodes applies network coding on packets belonging to the same batch. Previous works have studied the performance of BATS codes in the erasure channels, in which the packet loss rate ε is always assumed to be a constant on each link. However, in some application scenarios such as the Industrial Internet of Things (IIoTs) where there are a number of mobile nodes in the networks, the channel conditions could be time-variant due to the mobility of nodes, resulting the packet loss rate ε varying over time as well. Therefore this paper studies the rank distribution which is one of the most significant performance metric of BATS codes under time-variant channels by assuming the packet loss between links modeled as a random variable instead of a constant value. Closed-form expressions of rank distribution are obtained with the packet loss rate ε following two typical types of distributions. Both numerical and simulation results are provided to verify our analysis.

关键词： Packet loss Network coding Random variables Encoding Probability density function Gaussian distribution

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Mechanical behaviors and anchoring mechanism of coal-rock-bolt combinations under high strain rate conditions

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Journal of Rock Mechanics and Geotechnical engineering 2025年

作者： Fuqiang Ren Tianzuo Huang Chun Zhu Murat Karakus Yalong Jiang Yuan Chang School of Civil Engineering University of Science and Technology Liaoning Anshan 114051 China School of Earth Sciences and Engineering Hohai University Nanjing 210098 China Mining and Petroleum Engineering The University of Adelaide Adelaide South Australia 5005 Australia State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong University Nanchang 330013 China

Understanding the mechanical properties of coal-rock-bolt (CRB) combinations at high strain rates and the anchoring mechanism of bolts is crucial for ensuring the safety of coal mining operations. However, the dynamic behaviors of these combinations, especially the mechanism of action of prestressed bolts, still need to be further investigated. This study carried out split Hopkinson pressure bar (SHPB) tests on three sets of coal-rock (CR), CRB, and coal-rock-prestressed bolt (CRPB) combinations with different interface angles ( β = 15°, 30°, 45°, and 60°). The dynamic properties of the combinations were analyzed based on the stress-strain curve, energy dissipation, dynamic strength, fractal dimension of cracks, and failure mode of bolts. The test results show that a larger β will affect the stress transfer and anti-sliding ability of CR, resulting in a decrease in CR strength. The anchoring force of the bolt effectively suppresses the slip feature of CRB at the yield stage. As the strain rate increases, CRB shows a more pronounced 'sudden increase' in strength, and the bolt significantly enhances its dynamic strength. The prestressed bolts enhance the dynamic strength of CRPB while weaken the effect of β . The fractal dimension of the macrocracks increases with strain rate, with smaller variations in CRB and CRPB, indicating that the bolt reduces the complexity degree of CRB and CRPB. The anchoring force of CRB depends on bolt strength, which reduces the slip along the interface. The anchoring force of CRPB balances the coal-rock slip and suppresses crack formation, resulting in a more cohesive response under dynamic load.

关键词： Coal-rock-bolt combination Prestressed bolt High strain rates Dynamic response Anchoring mechanism

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An Efficient Evolutionary Algorithm for High-Speed Train Rescheduling Under a Partial Station Blockage

SSRN

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SSRN 2023年

作者： Wang, Rongsheng Zhang, Qi Dai, Xuewu Yuan, Zhiming Zhang, Tao Ding, Shuxin Jin, Yaochu China Academy of Railway Sciences Corporation Limited Beijing100081 China Signal and Communication Research Institute China Academy of Railway Sciences Corporation Limited Beijing100081 China Train Operation Control Laboratory for High-Speed Railway National Engineering Research Center of System Technology for High-Speed Railway and Urban Rail Transit Beijing100081 China State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang110819 China Faculty of Technology Bielefeld University BielefeldD-33615 Germany Department of Computer Science University of Surrey GuildfordGU2 7XH United Kingdom

This paper investigates the high-speed train rescheduling (HSTR) problem under a partial station blockage and proposes an efficient problem-specific strengthen elitist genetic algorithm (PS-SEGA) for HSTR. An HSTR model that is subject to train operation constraints is established to minimize the total train delay. The PS-SEGA framework consists of the following main steps. Firstly, a permutation-based encoding method is developed to define an efficient search space based on a train departure sequence. A decoding method is employed to output the rescheduled timetable and objective value based on the departure sequence. Moreover, a hybrid initialization method involving an efficient heuristic strategy (EHS) is put forward to accelerate the convergence speed of Evolutionary algorithms (EAs). Using problem-specific knowledge, EHS generates an efficient and feasible solution for the initial population. Finally, a restart strategy is presented to maintain genetic diversity. Compared with other advanced EAs and their improved variants also using the PS-SEGA framework, experimental results demonstrate the effectiveness of the proposed PS-SEGA for addressing HSTR scenarios under the partial station blockage. As for the scenarios that CPLEX can not obtain optimal solutions within 10 minutes, PS-SEGA can all provide quasi-optimal solutions in real-time. Furthermore, compared with the other two strategies (i.e., First-Scheduled-First-Served and EHS), PS-SEGA can find the best departure sequence that can output the timetable with a quasi-optimal solution. © 2023, The Authors. All rights reserved.

关键词： Genetic algorithms

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Passive instability of longitudinally inclined shallowly-buried shield tunnel using physical model tests and DEM simulations

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Underground Space 2025年

作者： Zhiwang Lu Youlin Ye Pengpeng Ni Zijie Qian Ben Niu Shijian Shang State Key Laboratory for Tunnel Engineering School of Civil Engineering Sun Yat-sen University Guangzhou 510275 China Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) Zhuhai 519082 China School of Transportation Engineering Dalian Jiaotong University Dalian 116021 China School of Transportation and Geomatics Engineering Shenyang Jianzhu University Shenyang 110168 China China Construction Sixth Engineering Bureau Limited Tianjin Rail Transit Branch Tianjin 300451 China

Stability of tunnel face is crucial, but previous studies often overlooked the effect of longitudinal tunnel inclination, leading to inaccurate stability assessments. In this study, nine groups of 1 g model tests were conducted to study the influence of longitudinal tunnel inclination on passive limit support pressure and passive failure mode of soil in front of the tunnel face under shallow burial conditions (i.e., cover depth ratio of 0.25, 0.50 and 0.75) in a sand stratum. In addition, discrete element method (DEM) analyses at the same scale were established and calibrated against the model test results. Accordingly, the micromechanical information of soil was derived from a microscopic perspective. The results indicate that upon the passive instability of tunnel face, the soil in front of the tunnel face firstly moved approximately perpendicular to the tunnel face, and then it deflected. The instability area of soil in front of the tunnel face increased with the decrease of longitudinal inclination, when the tunnel cover depth was fixed. Furthermore, microscopic analyses indicate that the longitudinal inclination could significantly affect the soil contact orientation in front of the tunnel face. This was more likely to cause the failure zone to rotate.

关键词： Tunnel face Passive failure Longitudinal inclination Model test DEM simulation

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A Novel Robust Dead-Beat Structure for Double Vector Model Predictive Control in Three-Level Inverter fed PMSM Drives

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IEEE Transactions on Power Electronics 2025年

作者： Sun, Zhenyao Wen, Junkai Yuan, Xin Ma, Guangtong Niu, Shuangxia Chau, K.T. The Hong Kong Polytechnic University Department of Electrical and Electronic Engineering 999077 Hong Kong University of Aberdeen School of Engineering AberdeenAB24 3UF United Kingdom Southwest Jiaotong University School of Electrical Engineering Chengdu610031 China Southwest Jiaotong University State Key Laboratory of Rail Transit Vehicle System Chengdu610031 China

Model predictive control (MPC) has recently been considered in permanent magnet synchronous motor (PMSM) drives due to its rapid dynamics and simple structure. However, conventional MPC utilizes only a single voltage vector per control cycle, and the prediction model relies heavily on the motor parameters. Hence, substantial current ripples and poor disturbance rejection have largely limited its adaptability to a variety of environment conditions. This paper presents a novel double vector MPC (DV-MPC) scheme for three-level inverter fed PMSM drives. To reduce the computational complexity of DV-MPC, the cost function is derived with the reference voltage by employing the dead-beat approach, and the inverter's neutral point potential is balanced using the complementary small voltage vectors. The dead-beat voltage prediction model is further enhanced by incorporating an active damping framework and an extra coefficient to enhance the robustness against parameter variations and disturbance rejection. Moreover, a robust current predictor is designed for the delay compensation. The proposed method is straightforward to implement, and achieves strong disturbance rejection and parameter robustness with a fast dynamic response. Experimental results demonstrate the effectiveness of the proposed method. © 1986-2012 IEEE.

关键词： Cost functions

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Automated inverse design of asymmetric excavation retaining structures using multiobjective optimization

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Journal of Rock Mechanics and Geotechnical engineering 2025年

作者： Qiwei Wan Changjie Xu Xiangyu Wang Haibin Ding Xiaozhen Fan State Key Laboratory of Performance Monitoring Protecting of Rail Transit Infrastructure East China Jiaotong University Nanchang 330021 China Australasian Joint Research Centre for Building Information Modelling Curtin University Perth GPO Box U1987 Australia College of Engineering Hangzhou City University Hangzhou 310015 China

Conventional pit excavation engineering methods often struggle to manage the complex deformation patterns associated with asymmetric excavations, resulting in significant safety risks and increased project costs. These challenges highlight the need for more precise and efficient design methodologies to ensure structural stability and economic feasibility. This research proposes an innovative automatic optimization inverse design method (AOIDM) that integrates an enhanced genetic algorithm (EGA) with a multiobjective optimization model. By combining advanced computational techniques with engineering principles, this approach improves search efficiency by 30% and enhances deformation control accuracy by 25%. Additionally, the approach exhibits potential for reducing carbon emissions to align with sustainable engineering goals. The effectiveness of this approach was validated through comprehensive data analysis and practical case studies, demonstrating its ability to optimize retaining structure designs under complex asymmetric loading conditions. This research establishes a new standard for precision and efficiency in automated excavation design, with accompanying improvements in safety and cost-effectiveness. Furthermore, it lays the foundation for future geotechnical engineering advancements, offering a robust solution to one of the most challenging aspects of modern excavation projects.

关键词： Multiobjective optimization enhanced genetic algorithm (EGA) Inverse design Deformation control Economic optimization

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Improving the surface charge density of multi-layered triboelectric nanogenerator by dual-electric field mutual inductance

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Chemical engineering Journal 2025年 516卷

作者： Changcheng Bao Min He Jianping Li Yili Hu Jijie Ma Jianming Wen Yingting Wang Xiaoxia Ma The Institute of Precision Machinery and Smart Structure College of Engineering Zhejiang Normal University Yingbin Street 688 Jinhua 321004 China Key Laboratory of Intelligent Operation and Maintenance Technology & Equipment for Urban Rail Transit of Zhejiang Province Zhejiang Normal University Yingbin Street 688 Jinhua 321004 China State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of Technology Beijing 100081 China

As a novel energy harvesting technology, triboelectric nanogenerator (TENG) has emerged as a research hotspot in recent years due to its efficient energy conversion capabilities and broad application prospects. However, due to the limitations of the dielectric properties of friction materials, it is difficult for TENG to achieve a high surface charge density in a limited space. Dual-electric field mutual inductance strategy provides an effective method to improve the surface charge density of TENG devices. Herein, we investigate the surface charge density of a multi-layer structure TENG based on the mechanism of dual-electric field mutual inductance. Experimental research has verified the existence of interaction between electric fields in a multi-layered TENG based on a dual-electric field mutual inductance strategy. Tests of the electrical connection method show that in multi-layered mutual inductance units, the output superposition is achieved by introducing an external charge to the side opposite to the potential change of the output terminal, and the friction layer in parallel on the same side effectively maximizes the output power. In the case of parallel-connected three-layer mutual inductance units, when the multi-layered TENG is used to supply power to a capacitor of the same capacity, the charging rate after introducing an external charge is about three times that of the original state. This study provides theoretical guidance for optimizing the performance of multi-layered TENG using the dual-electric field mutual inductance strategy and offers innovative solutions for sustainable energy utilization.

关键词： Dual-electric field Multi-layered triboelectric nanogenerator Mutual inductance Surface charge density

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