Fracture Modeling of the Bi-Block Ballastless Track System Resulting from Early-Aged Relative Humidity during the Construction Process

Fracture Modeling of the Bi-Block Ballastless Track System Resulting from Early-Aged Relative Humidity during the Construction Process

Drying-induced cracks are an important issue for bi-block ballastless track system consisting of foundation, precast sleepers, and cast-in-place track slab, which not only significantly affects the comfortableness and safety of rapid transit railway but also reduces the service life of ballastless t...

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Autores principales: Shihao Cao, Wang Hui, Shufang Zhai, Kui Hu, Yujing Chen, Junqi Chen
Formato: article
Lenguaje:EN
Publicado: Hindawi Limited 2021
Materias:
Engineering (General). Civil engineering (General)
TA1-2040
Acceso en línea:https://doaj.org/article/accd48901ac346d184a5ad1394abeeb4
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spelling oai:doaj.org-article:accd48901ac346d184a5ad1394abeeb42021-11-08T02:37:03ZFracture Modeling of the Bi-Block Ballastless Track System Resulting from Early-Aged Relative Humidity during the Construction Process1687-809410.1155/2021/2511582https://doaj.org/article/accd48901ac346d184a5ad1394abeeb42021-01-01T00:00:00Zhttp://dx.doi.org/10.1155/2021/2511582https://doaj.org/toc/1687-8094Drying-induced cracks are an important issue for bi-block ballastless track system consisting of foundation, precast sleepers, and cast-in-place track slab, which not only significantly affects the comfortableness and safety of rapid transit railway but also reduces the service life of ballastless track. In order to explore its damage mechanism, this work presents an evolution model of relative humidity (RH) in the CRTS I bi-block ballastless track system by considering the actual construction sequence and environmental conditions to simulate the crack propagation induced by nonuniform RH field. Firstly, based on the node coupling technique, a three-step transfer process of RH is designed to separately investigate the influence of the construction sequence on the early humidity field in the foundation, sleepers, and cast-in-place track slab, and then the nonuniform distribution of early humidity field in the ballastless track system is determined. Subsequently, the formation mechanism of shrinkage crack in the system is analyzed, and the crack propagation path is predicted by using the mixed-mode fracture criterion. The results show that the maximum relative humidity gradient (RHG) appears at the interface between the track slab and the sleeper after concreting the cast-in-place track slab, which causes the maximum principal stress due to the drying shrinkage property of concrete materials. When the maximum principal stress exceeds the tensile strength of the interface, an interface crack will be generated and converted to a splayed crack with an initial angle of about 45° at the sleeper corner, which will be further propagated under the action of drying shrinkage deformation and finally forms a transverse through-wall crack in the track slab. The simulated crack propagation path agrees with the observed one at the site well, and thus the results are beneficial to understand the formation mechanism of through-wall crack in the track slab and further guide the construction design of the bi-block ballastless track system.Shihao CaoWang HuiShufang ZhaiKui HuYujing ChenJunqi ChenHindawi LimitedarticleEngineering (General). Civil engineering (General)TA1-2040ENAdvances in Civil Engineering, Vol 2021 (2021)
institution DOAJ
collection DOAJ
language EN
topic Engineering (General). Civil engineering (General)
TA1-2040
spellingShingle Engineering (General). Civil engineering (General)
TA1-2040
Shihao Cao
Wang Hui
Shufang Zhai
Kui Hu
Yujing Chen
Junqi Chen
Fracture Modeling of the Bi-Block Ballastless Track System Resulting from Early-Aged Relative Humidity during the Construction Process
description Drying-induced cracks are an important issue for bi-block ballastless track system consisting of foundation, precast sleepers, and cast-in-place track slab, which not only significantly affects the comfortableness and safety of rapid transit railway but also reduces the service life of ballastless track. In order to explore its damage mechanism, this work presents an evolution model of relative humidity (RH) in the CRTS I bi-block ballastless track system by considering the actual construction sequence and environmental conditions to simulate the crack propagation induced by nonuniform RH field. Firstly, based on the node coupling technique, a three-step transfer process of RH is designed to separately investigate the influence of the construction sequence on the early humidity field in the foundation, sleepers, and cast-in-place track slab, and then the nonuniform distribution of early humidity field in the ballastless track system is determined. Subsequently, the formation mechanism of shrinkage crack in the system is analyzed, and the crack propagation path is predicted by using the mixed-mode fracture criterion. The results show that the maximum relative humidity gradient (RHG) appears at the interface between the track slab and the sleeper after concreting the cast-in-place track slab, which causes the maximum principal stress due to the drying shrinkage property of concrete materials. When the maximum principal stress exceeds the tensile strength of the interface, an interface crack will be generated and converted to a splayed crack with an initial angle of about 45° at the sleeper corner, which will be further propagated under the action of drying shrinkage deformation and finally forms a transverse through-wall crack in the track slab. The simulated crack propagation path agrees with the observed one at the site well, and thus the results are beneficial to understand the formation mechanism of through-wall crack in the track slab and further guide the construction design of the bi-block ballastless track system.
format article
author Shihao Cao
Wang Hui
Shufang Zhai
Kui Hu
Yujing Chen
Junqi Chen
author_facet Shihao Cao
Wang Hui
Shufang Zhai
Kui Hu
Yujing Chen
Junqi Chen
author_sort Shihao Cao
title Fracture Modeling of the Bi-Block Ballastless Track System Resulting from Early-Aged Relative Humidity during the Construction Process
title_short Fracture Modeling of the Bi-Block Ballastless Track System Resulting from Early-Aged Relative Humidity during the Construction Process
title_full Fracture Modeling of the Bi-Block Ballastless Track System Resulting from Early-Aged Relative Humidity during the Construction Process
title_fullStr Fracture Modeling of the Bi-Block Ballastless Track System Resulting from Early-Aged Relative Humidity during the Construction Process
title_full_unstemmed Fracture Modeling of the Bi-Block Ballastless Track System Resulting from Early-Aged Relative Humidity during the Construction Process
title_sort fracture modeling of the bi-block ballastless track system resulting from early-aged relative humidity during the construction process
publisher Hindawi Limited
publishDate 2021
url https://doaj.org/article/accd48901ac346d184a5ad1394abeeb4
work_keys_str_mv AT shihaocao fracturemodelingofthebiblockballastlesstracksystemresultingfromearlyagedrelativehumidityduringtheconstructionprocess
AT wanghui fracturemodelingofthebiblockballastlesstracksystemresultingfromearlyagedrelativehumidityduringtheconstructionprocess
AT shufangzhai fracturemodelingofthebiblockballastlesstracksystemresultingfromearlyagedrelativehumidityduringtheconstructionprocess
AT kuihu fracturemodelingofthebiblockballastlesstracksystemresultingfromearlyagedrelativehumidityduringtheconstructionprocess
AT yujingchen fracturemodelingofthebiblockballastlesstracksystemresultingfromearlyagedrelativehumidityduringtheconstructionprocess
AT junqichen fracturemodelingofthebiblockballastlesstracksystemresultingfromearlyagedrelativehumidityduringtheconstructionprocess
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