Soheili, Rozhin;
(2023)
Monotonic and cyclic behaviour of scaled railway ballast with and without cement by using the triaxial apparatus.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
The rail system is a reliable transportation mode and is in everyday life. But nowadays, the cost of track maintenance surpasses half a billion a year and corresponds to approximately a quarter of the operational budget. The majority of the problems occur in the ballast layer and settlements, due to densification or caused by maintenance work are the main causes of delays and line closures. Therefore, new ways of reducing track maintenance and increasing the life span of ballast are important. This research focuses on understanding how a binder can contribute to the improvement of the mechanical properties of the ballast in areas related to settlement and consequent maintenance reduction. Monotonic and cyclic triaxial tests were performed in scaled ballast samples with and without cement, at different confining pressures and stress ratios and to a high number of cycles. The breakage generated during shearing at different testing stages was also analysed. The results show that the addition of a binder increases the strength and the stiffness of the ballast. It also shows that the addition of light cementation reduces dramatically the settlement caused by the cyclic loading. It also allows the ballast to reach much higher stress ratios without failing to excessive deformation. The results show that cemented ballast has the potential to reduce settlements caused by fatigue or train load, consequently extending maintenance periods. The results also show that the cemented ballast generates a much smaller amount of fines during cyclic loading, reducing the occurrence of ballast fouling. Another advantage of the low cementation is that the bonds are easily broken by traditional machinery, therefore there is no need to invest in new and specialised equipment.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Monotonic and cyclic behaviour of scaled railway ballast with and without cement by using the triaxial apparatus |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2023. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Civil, Environ and Geomatic Eng |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10166011 |
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