Influences of Subgrade Form and Ground Stiffness on Dynamic Responses of Railway Subgrade under Train Loading: Field Testing Case Study

Xiao, Junhua; Wang, Binglong; Liu, Chengyu; Yu, Zheng

doi:10.1016/j.proeng.2016.06.123

Cited by 17 publications

(5 citation statements)

References 2 publications

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“…The fill and cut portions were built by Xiao et al [24] in compliance with the design code for a 200 km/h railway subgrade. Train loading tests were used to examine the impact of subgrade development on dynamic response in the fill section.…”

Section: Introductionmentioning

confidence: 99%

Stresses in Saturated and Unsaturated Subgrade Layer Induced by Railway Track Vibration

Fattah,

Majeed,

Joni

2024

Infrastructures

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The theoretical and practical studies of the cyclic loads resulting from the movement and passage of trains on the unsaturated subgrade to determine the effect of the degree of saturation and moisture content on the foundations and infrastructure of the railway lines, especially the settlement in the railway lines as a result of the development of the train loads. Thirty-six laboratory experiments were carried out using models that simulate a railway with nearly half the scale of the real one, using an iron box of (1.5 × 1.0 × 1.0) meters and a layer of clay soil with a thickness of 0.5 m representing the base layer, were constructed inside it. Above it, there is a layer of crushed stone representing a 0.2 m thick ballast, topped by a rail line of 0.8 m long installed on three sleeper beams with dimensions of 0.9 m (0.1 × 0.1 m). The subgrade layer has been constructed at different saturation degrees as follows: 100, 80, 70, and 60%. The tests were carried out using different load amplitudes and frequencies. These experiments investigated the effect of the subgrade degree of saturation on the value of the stresses generated on the surface and the middle (vertical and lateral stresses) and the settlement of the subgrade. In the case of unsaturated subgrade soil, an increase in load frequency has a clear effect on increasing the generated stresses in the subgrade layer, especially with lower saturation levels. However, the results and measurements of these experiments found that the load frequency almost had no effect on the values of the stresses generated on the surface and inside the subgrade layer with a 100% degree of saturation. The results of the investigation demonstrated that, while load frequency had a minimal effect on track-panel settlement, it increased with the load amplitude and subgrade soil saturation degree. The change of settlement of the track panel with the number of cycles has a high rate at the beginning; after a while from that, it decreases gradually until, after some value of the number of cycles, the settlement changes at a very low rate and gradually.

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Section: Introductionmentioning

confidence: 99%

Stresses in Saturated and Unsaturated Subgrade Layer Induced by Railway Track Vibration

Fattah,

Majeed,

Joni

2024

Infrastructures

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“…As is well known, numerical simulation is also a powerful technique to evaluate the mechanical performance of a track–subgrade system. Nevertheless, it generally simulates the real condition with many assumptions and simplifications on the boundary conditions and distribution of the soil properties, and thus leads to difficulty in validating the accuracy and effectiveness of the calculation results, and in situ experimental results are usually required for verification [ 13 , 25 , 26 ]. Moreover, although it is more persuasive to perform a full-scale model test to investigate the dynamic response of prestressed subgrade, this method is rather time-consuming and expensive as well, and a more advanced and powerful testing platform is required.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Response Characteristics of Railway Subgrade Using a Newly-Developed Prestressed Reinforcement Structure: Case Study of a Model Test

et al. 2022

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Poor subgrade conditions usually induce various subgrade diseases in railways, leading to some adverse influences. An innovative technology that involves installing a prestressed reinforcement structure (PRS) that consists of steel bars and lateral pressure plates (LPP) for subgrade was introduced to improve its stress field and provide compulsive lateral deformation constraints for slope. In this study, an investigation into the dynamic acceleration responses of railway subgrade strengthened according to different PRS schemes was presented using a 1:5 scale model test, aiming to explore the effects of the axle load, the reinforcement pressure, and the loading cycles on the acceleration characteristics of the subgrade. The experimental results showed that (1) after pretension of the steel bar, prestress loss occurred due to the soil creep behavior and group anchor effect, so a moderate amount of over-tension in practices would be necessary; (2) a distinctive periodical behavior of subgrade subjected to the cyclic loads was observed, the horizontal accelerations were generally less than the vertical accelerations at the same measurement heights, and the vibration energy attenuated gradually from the shoulder to the toe along the slope; (3) in the short-term tests, the peak accelerations at all measurement points had a linear correlation with the axle load, and oppositely, it showed an approximately linear decrease with the increasing reinforcement pressure; And (4) in the long-term tests, to simulate the heavy haul wagon with a 35 t axle load, the variation in the effective acceleration with loading cycles under reinforcement pressure 100 kPa initially exhibited a decrease and subsequently tended to be stable, which is apparently less than that without reinforcement pressure. Consequently, it was demonstrated that the PRS itself and increasing reinforcement pressure can effectively mitigate the subgrade vibration, and provide an appropriate alternative to improve the dynamic performance of railway subgrade under the moving train loads.

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“…Previous research usually focused on indoor model test and numerical simulation. But as the most direct method for subgrade vibration response characteristics, field tests conducted in China [28,29], France [30], Germany [31], and UK [32] provided an important basis for the study of subgrade vibration response characteristics. However, there are few field test studies on the vibration response and attenuation law of the diseased subgrade, and the characteristics of the vibration response of the diseased subgrade for a railway line are not definite at present.…”

Section: Introductionmentioning

confidence: 99%

Vibration Response Characteristics and Application of Existing Railway Subgrade

Zhang

Chen

et al. 2021

Shock and Vibration

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The existing conventional methods of subgrade disease assessment are not suitable for the existing lines. There are many research studies on the vibration response and attenuation law of the railway subgrade, but few research studies focus on the vibration response and attenuation law caused by the weak subgrade. In this study, vibration response tests were carried out at different positions and depths of the subgrade before and after reinforcement improvement. The results show that vibration response near the ballast is obvious, and it attenuates with the increase of the horizontal distance from the rail; the vibration acceleration response of the subgrade after reinforcement changes greatly; the vibration response curve of the reinforced section is spindle shaped, and the vertical vibration acceleration response attenuates obviously at the depth of 6.5 m, only about 10% to 30% of the surface; the vibration acceleration of the subgrade with reinforcement at the depth of 4.5 m attenuates to 60% of the surface; the vibration acceleration of the subgrade without reinforcement at the depth of 4.5 m attenuates to 50%–60% of the surface.

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Influences of Subgrade Form and Ground Stiffness on Dynamic Responses of Railway Subgrade under Train Loading: Field Testing Case Study

Cited by 17 publications

References 2 publications

Stresses in Saturated and Unsaturated Subgrade Layer Induced by Railway Track Vibration

Stresses in Saturated and Unsaturated Subgrade Layer Induced by Railway Track Vibration

Dynamic Response Characteristics of Railway Subgrade Using a Newly-Developed Prestressed Reinforcement Structure: Case Study of a Model Test

Vibration Response Characteristics and Application of Existing Railway Subgrade

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