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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| Format: | Article |
| Language: | English |
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Wiley
2021-01-01
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| Series: | Advances in Civil Engineering |
| Online Access: | http://dx.doi.org/10.1155/2021/2511582 |
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| 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 |
| collection | DOAJ |
| 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 |
| id | doaj-art-accd48901ac346d184a5ad1394abeeb4 |
| institution | OA Journals |
| issn | 1687-8086 1687-8094 |
| language | English |
| publishDate | 2021-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Civil Engineering |
| spelling | doaj-art-accd48901ac346d184a5ad1394abeeb42025-08-20T02:20:23ZengWileyAdvances in Civil Engineering1687-80861687-80942021-01-01202110.1155/2021/25115822511582Fracture Modeling of the Bi-Block Ballastless Track System Resulting from Early-Aged Relative Humidity during the Construction ProcessShihao Cao0Wang Hui1Shufang Zhai2Kui Hu3Yujing Chen4Junqi Chen5College of Civil Engineering, Henan University of Technology, Zhengzhou 450001, ChinaSchool of Civil Engineering and Architecture, Hainan University, Haikou 570228, ChinaCollege of Civil Engineering, Henan University of Technology, Zhengzhou 450001, ChinaCollege of Civil Engineering, Henan University of Technology, Zhengzhou 450001, ChinaCollege of Civil Engineering, Henan University of Technology, Zhengzhou 450001, ChinaCollege of Civil Engineering, Henan University of Technology, Zhengzhou 450001, ChinaDrying-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.http://dx.doi.org/10.1155/2021/2511582 |
| spellingShingle | 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 Advances in Civil Engineering |
| title | 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_short | 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 |
| url | http://dx.doi.org/10.1155/2021/2511582 |
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