Experimental research on the dynamic response characteristics of the transition subgrade induced by heavy-haul train passage

2019 ◽  
Vol 233 (9) ◽  
pp. 974-987 ◽  
Author(s):  
Huihao Mei ◽  
Wuming Leng ◽  
Rusong Nie ◽  
Renpan Tu ◽  
Yafeng Li ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Repeated Loading ◽  
Moving Loads ◽  
Response Characteristics ◽  
Heavy Haul Train ◽  
Condition Evaluation ◽  
Heavy Haul ◽  
Variation Characteristics ◽  
Heavy Haul Railway ◽  
Moving Train

The dynamic response of the subgrade under moving train loads provides information on subgrade settlement prediction, condition evaluation, and so forth. This paper presents the field dynamics tests on the transition subgrade in the Shuo-Huang heavy-haul railway in China. The variation characteristics of the peak dynamic displacements along the track and subgrade slope were analyzed, and the random distribution characteristics of the peak dynamic displacements at the subgrade shoulder were studied. The response characteristics of the subgrade during the train passage were investigated, and the attenuation regularities of vibration along the subgrade slope were identified. The results indicated that the action of the train moving loads on the subgrade has obvious periodicity, and two bogies in the adjacent wagons should be considered as one loading unit. The peak dynamic displacements at the subgrade shoulder obey normal distribution under the repeated loading of the loading unit. The subgrade bed is dramatically influenced by the dynamic loadings of the trains, and the moving train loads have little influence on the part below the subgrade bed. The results of the research provide the basis for the evaluation of instantaneous and long-term dynamic stability of the subgrade and offer guidance for simulating train moving loads in the model test and numerical analysis to study the dynamic response of the subgrade.

scholarly journals The Influence of Track Structure Parameters on the Dynamic Response Sensitivity of Heavy Haul Train-LVT System

2021 ◽  
Vol 11 (24) ◽  
pp. 11830
Author(s):  
Zhi-Ping Zeng ◽  
Yan-Cai Xiao ◽  
Wei-Dong Wang ◽  
Xu-Dong Huang ◽  
Xiang-Gang Du ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Track Structure ◽  
Lateral Stiffness ◽  
Structure Parameters ◽  
Response Sensitivity ◽  
Vertical Stiffness ◽  
Rail System ◽  
Heavy Haul Train ◽  
Heavy Haul ◽  
Heavy Haul Railway

Background: In order to study the applicability of Low Vibration Track (LVT) in heavy-haul railway tunnels, this paper carried out research on the dynamic effects of LVT heavy-haul railway wheels and rails and provided a technical reference for the structural design of heavy-haul railway track structures. Methods: Based on system dynamics response sensitivity and vehicle-track coupling dynamics, the stability of the upper heavy-haul train, the track deformation tendency, and the dynamic response sensitivity of the vehicle-track system under the influence of random track irregularity and different track structure parameters were calculated, compared and analyzed. Results: Larger under-rail lateral and vertical structural stiffness can reduce the dynamic response of the rail system. The vertical and lateral stiffness under the block should be set within a reasonable range to achieve the purpose of reducing the dynamic response of the system, and beyond a certain range, the dynamic response of the rail system will increase significantly, which will affect the safety and stability of train operation. Conclusions: Considering the changes of track vehicle body stability coefficients, the change of deformation control coefficients, and the sensitivity indexes of dynamic performance coefficients to track structure stiffness change, the recommended values of the vertical stiffness under rail, the lateral stiffness under rail, the vertical stiffness under block, and the lateral stiffness under block are, respectively 160 kN/mm, 200 kN/mm, 100 kN/mm, and 200 kN/mm.

scholarly journals Research on Dynamic Response Characteristics for Basement Structure of Heavy Haul Railway Tunnel with Defects

Mathematics ◽  
2021 ◽  
Vol 9 (22) ◽  
pp. 2893
Author(s):  
Jinfei Chai
Keyword(s):  
Constitutive Model ◽  
Dynamic Response ◽  
Principal Stress ◽  
Surrounding Rock ◽  
Railway Tunnel ◽  
Basement Structure ◽  
Measuring Point ◽  
Heavy Haul ◽  
Damage Constitutive Model ◽  
Heavy Haul Railway

Based on the basic principle of thermodynamics, an elastoplastic damage constitutive model of concrete is constructed in this paper. The model is realized and verified in FLAC3D, which provides a solid foundation for the study of dynamic response and fatigue damage to the base structure of a heavy haul railway tunnel. The dynamic response and damage distribution of the base structure of a heavy-duty railway tunnel with defects were numerically simulated by the concrete elastic-plastic damage constitutive model. Then, by analyzing the response characteristics of the tunnel basement structure under different surrounding rock softening degrees, different foundation suspension range and different foundation structure damage degree are determined. The results show the following: (1) The elastoplastic damage constitutive model of concrete can well describe the stress–strain relationship of materials, especially with the simulation results of post peak softening being in good agreement with the test results, and the simulation effect of the unloading–reloading process of the cyclic loading and unloading test also meet the requirements. (2) The initial stress field and dynamic response of the tunnel basement structure under the action of train vibration load are very different from the ideal state of the structure design when the surrounding rock of the base is softened, the base is suspended, or the basement structure is damaged. With the surrounding rock softening, basement hanging, or basement structure damage developing to a certain extent, the basement structure will be damaged. (3) The horizontal dynamic stress amplitude increases with the increase in the softening degree of the basement surrounding rock. The horizontal dynamic stress of the measuring point increases with the increase in the width of the hanging out area when the hanging out area is located directly below the loading line. When the degree of damage to the basement structure is aggravated, the horizontal dynamic tensile stress of each measuring point gradually decreases. (4) The maximum principal stress increment increases with the increase in the fracture degree of the basement structure, while the minimum principal stress increment decreases with the increase in the fracture degree of the basement structure, but the variation range of the large and minimum principal stress increments is small. The research results have important theoretical and practical significance for further analysis of the damage mechanism and control technology of the foundation structure of a heavy haul railway tunnel with defects.

scholarly journals Exploration of key traction-running equipment and its problems on heavy-haul trains and research on technology development

2020 ◽  
Vol 2 (3) ◽  
pp. 161-182
Author(s):  
Chunyang Chen ◽  
Wei Li ◽  
Youmei Liu ◽  
Xiang Wei
Keyword(s):  
Technology Development ◽  
Rolling Stock ◽  
Practical Applications ◽  
Technical Developments ◽  
Heavy Haul Train ◽  
Heavy Haul ◽  
Traction Equipment ◽  
Heavy Haul Trains ◽  
Technology Control ◽  
Heavy Haul Railway

Abstract In recent years, heavy-haul train technology has seen a number of innovations worldwide, and train traction-running technology has also made great progress, resulting in a rich pool of experience and a range of promising applications. This paper summarizes the key technologies of traction running in heavy-haul combined trains, especially locomotive and rolling-stock technology, traction technology, braking technology, control technology, communication technology and safety technology. At the same time, based on an analysis of practical applications, this paper further explores the main problems and urgent needs of traction equipment on heavy-haul trains. With an eye to the future, the heavy-haul railway system will develop in the direction of informatization, automation and intelligence, in order to build a greener, more energy-saving, safer and more efficient railway. This paper therefore looks forward to the technical developments of heavy-haul combined trains, and provides a reference for the development of heavy-haul railways.

Field Test Study on the dynamic response of the cement-improved expansive soil subgrade of a heavy-haul railway

2020 ◽  
Vol 128 ◽  
pp. 105878 ◽  
Author(s):  
Yu Cai ◽  
Linrong Xu ◽  
Weizheng Liu ◽  
Yonghui Shang ◽  
Na Su ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Field Test ◽  
Expansive Soil ◽  
Test Study ◽  
Heavy Haul ◽  
Heavy Haul Railway

scholarly journals MODEL-BASED ASSESSMENT OF LONGITUDINAL DYNAMIC PERFORMANCE AND ENERGY CONSUMPTION OF HEAVY HAUL TRAIN ON LONG-STEEP DOWNGRADES

Transport ◽  
2019 ◽  
Vol 34 (3) ◽  
pp. 250-259
Author(s):  
Jin Shi ◽  
Shujing Ren ◽  
Mengran Zhang
Keyword(s):  
Energy Consumption ◽  
Dynamic Performance ◽  
Analytical Tool ◽  
Longitudinal Dynamic ◽  
Heavy Haul Train ◽  
Heavy Haul ◽  
Longitudinal Profiles ◽  
Heavy Haul Trains ◽  
Heavy Haul Railway ◽  
Central South

Longitudinal dynamics performance and energy consumption of heavy haul train should be considered in the design of heavy haul railway profile of long-steep downgrades. A quantitative analytical tool is developed to assess the longitudinal dynamic performance and energy consumption of heavy haul trains with large axle loads on grades with different longitudinal profiles, including a longitudinal dynamic model of the train and a method of calculating the energy consumption during the operation of heavy haul train. The model is then preliminarily validated by the data of coupler force collected in two comprehensive tests. Finally, the proposed analytical tool is used to assess the designed longitudinal track profile of a long-deep downgrade segment of the central south heavy haul railway of Shanxi (China).

scholarly journals Dynamic Response of Railway Bridges under Heavy-Haul Freight Trains

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Ye Xiao ◽  
Xiaoyong Luo ◽  
Jinhong Liu ◽  
Kun Wang
Keyword(s):  
Dynamic Response ◽  
Fe Model ◽  
Bridge Structure ◽  
Railway Bridge ◽  
Running Speed ◽  
Railway Bridges ◽  
Heavy Haul ◽  
Formation Number ◽  
Axle Loads ◽  
Heavy Haul Railway

In the freight railway bridge, the increase of the train running speed and train axle loads can enlarge dynamic response (DR) of the railway bridges, which leads to excessive vibration of bridges and endangers the structural safety. In this paper, a three-dimensional coupled finite element (FE) model of a heavy-haul freight train-track-bridge (HHFTTB) is established using multibody dynamics theory and FE method, and the DR for the coupled system of HHFTTB are solved by ABAQUS/Explicit dynamic analysis method. The field-measured data for a 32 m simply supported prestressed concrete beam of a heavy-haul railway in China are analyzed, and the validity of the FE model is verified. Finally, the effects of train formation number, train running speed, and train axle loads on DR of the heavy-haul railway bridge structures are studied. The results show that increasing the train formation number only has an influence on DR duration of the bridge structure, rather than the peak value of DR, when the train formation number exceeds a certain number; besides, the train axle loads and train running speed have significant influence on DR of the bridge structure. The results of this study can be used as reference for the design of heavy-haul railway bridges and the reinforcement transformation of existing railway bridges.

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