Use of Leca lightweight aggregate in railway structures
Loading...
URL
Journal Title
Journal ISSN
Volume Title
Insinööritieteiden korkeakoulu |
Master's thesis
Unless otherwise stated, all rights belong to the author. You may download, display and print this publication for Your own personal use. Commercial use is prohibited.
Authors
Date
2021-06-14
Department
Major/Subject
Geotechnical Engineering
Mcode
Degree programme
Master's Programme in Geoengineering
Language
en
Pages
87+12
Series
Abstract
Railway embankment design plays an important role in ensuring comfort, safety and timely operation of railways, which are the three greatest concerns for railway passengers and operators. When adopting a material for railway embankments, it is necessary to evaluate the material in terms of its geotechnical design. To demonstrate the use of Leca LWA in railway structures, this thesis determined a suitable cover depth and an optimal location for Leca LWA in railway embankments, as well as evaluated the effect of high-cycle loads on Leca LWA. These aims were achieved by analyzing and simulating key aspects in railway geotechnical design, such as bearing capacity, embankment stability and the displacement induced by cyclic loading. Simulation results demonstrated that the optimal location for Leca LWA is below a 300-mm thick extra subballast layer. Such a setting could significantly improve not only the bearing capacity at the top of the subballast layer but also the stability of railway embankments. When the thickness of the extra subballast layer exceeded 300 mm, no clear improvement was observed in these two aspects of railway geotechnical design. Regarding the effect of cyclic loading on Leca LWA, it was found that the material could sufficiently bear such loading regardless of the cover depth. However, these findings are limited to the cross section studied in this work, which consisted of a 550-mm thick ballast layer followed by a 300-mm thick subballast layer, with a maximum embankment height of 2.5 m, onto which was applied a maximum axle load of 25 tons. The suitable cover depth of 1150 mm, consisting of a 550-mm thick ballast layer, followed by a 300-mm thick subballast layer and a 300-mm thick extra subballast layer, is recommended to be constructed above a Leca LWA layer. These results could provide guidelines for geotechnical designers in effectively using Leca LWA as a railway embankment material. Additionally, this thesis has established the feasibility of using the HCA model and the Plaxis SSC model to simulate the accumulated plastic strain resulting from high-cycle loads caused by moving trains.Description
Supervisor
Solowski, WojciechThesis advisor
Savolainen, LauriDettenborn, Taavi
Keywords
lightweight aggregate, cyclic loading, railway embankment design, high-cycle accumulation model