Interlocking Settlement Induced by Widening Subgrade of Railway Line

Kim, Dae Sang; Kim, Ung-Jin; Park, Young Kon

doi:10.3390/app12136638

Cited by 2 publications

(2 citation statements)

References 24 publications

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“…However, since the newly built subgrade and foundation have not been subjected to the long-term overburden surcharge, large settlement deformation may occur, resulting in the obvious differential settlement between the new and old subgrade [2]. In addition, it has been shown that excessive differential settlement will lead to longitudinal cracking of the joints between old and new pavement [3], thus affecting the normal operation of the roads [4,5]. Therefore, it is of great significance to study post-construction differential settlement for highway-widening projects.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Differential Settlement of Subgrade for Highway-Widening Projects

et al. 2023

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Highway widening is an important way to improve the existing expressway capacity and promote the development of transportation systems. The differential settlement between the old and new subgrade is the key factor to evaluate whether it is necessary to carry out ground improvement for the new foundation, which will cause longitudinal pavement cracking and even subgrade instability. Therefore, the most critical task in the highway expansion project is controlling differential settlement, particularly post-construction differential settlement. In this study, a fluid-structure coupling settlement analysis model was developed based on FLAC3D, and a modified Cam-clay (MCC) model was used to describe the difference between new and old foundation parameters. The working conditions of different subgrade heights and groundwater levels were simulated to analyze their influence on the differential settlement during and after construction. With the increment value of the transverse slope (∆i) and maximum slope (k) of new and old subgrade settlement curves as evaluation indexes, the differential settlement size of widened subgrade under different working conditions is evaluated, which provides a basis for the design of widened foundation engineering and provides suggestions on whether reinforcement measures should be taken. The results show that the post-construction differential settlement increases with the increase in groundwater level and subgrade height. Under the requirement of ∆i ≤ 0.5%, it is not necessary to take reinforcement measures under the condition of local water levels under a 2 m subgrade height and −9 m and −11 m groundwater levels under a 4 m subgrade height. However, when the water level rises further, or the height of the subgrade increases further, it is necessary to take foundation reinforcement measures. Meanwhile, for the requirement of k ≤ 0.5%, foundation reinforcement measures should be taken for all working conditions regardless of the water level or subgrade height. The research results can provide theoretical value and reference for foundation treatment in roadbed-widening engineering.

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Section: Introductionmentioning

confidence: 99%

“…At present, there is research on how to control differential settlement [5,[24][25][26][27][28]. However, it can be found that the influence of groundwater on subgrade differential settlement is not very clear, and the control index of subgrade differential settlement is not universal.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Differential Settlement of Subgrade for Highway-Widening Projects

et al. 2023

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Model Test Study of the Synergistic Interaction between New and Existing Components of Sheet Pile Walls

Zhao

2023

Applied Sciences

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New and existing components of retaining structures are often combined in the width section. When combining the design and use requirements of the existing and new structures, the synergistic interactions between the existing and new structures and the design and working conditions require clarification. In conjunction with an actual project, a sheet pile wall consisting of existing and new components is proposed to retain an embankment. Indoor model tests were carried out to simulate the excavation and compaction and investigate changes in earth pressure, pile bending moment, shear force, and load-sharing ratio of the new and existing sheet pile walls at different stages. The results show that the earth pressure of the cantilever section of the existing and new piles increases with an increase in the fill volume or the upper uniform load. An inflection point is observed in the earth pressure curve halfway between the pile top and the ground due to sudden changes in the pile and soil stiffness. The bending moment of the new and existing piles increases and decreases with the distance from the top of the pile under different working conditions, and the maximum bending moment occurred at 0.485 and 0.9 m from the bottom of the existing pile and the bottom of the new pile, respectively. The lateral displacement of the new and existing piles decreases with the distance from the top of the pile. Due to the adjustment of the structural force in the cantilever section and the soil reaction force in front of the pile, the displacement curves of the new and existing piles are similar in the cantilever section. The displacement in the anchored section is initially larger for the existing pile than for the new pile but then becomes similar for both piles. In working condition 5, the top displacement of the existing pile was 6.531 mm, exceeding the control value (5.6 mm). The earth-pressure-sharing ratio of the existing pile decreases with an increase in the width of the filling material or the load. When the load was applied, the earth-pressure-sharing ratio of the existing pile was 0.451, indicating that the structural design of the combined sheet pile wall is reasonable.

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Interlocking Settlement Induced by Widening Subgrade of Railway Line

Cited by 2 publications

References 24 publications

Evaluation of Differential Settlement of Subgrade for Highway-Widening Projects

Evaluation of Differential Settlement of Subgrade for Highway-Widening Projects

Model Test Study of the Synergistic Interaction between New and Existing Components of Sheet Pile Walls

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