Connolly, DP and Costa, PA (2020) Geodynamics of very high speed transport systems. Soil Dynamics and Earthquake Engineering, 130. ISSN 0267-7261
Abstract
This work reveals the existence of a new dynamic load amplification mechanism due to ground surface loads. It is caused by the interaction between a moving vehicle's axle configuration and the vibration characteristics of the underlying soil-guideway system. It is more dominant than the traditionally considered ‘critical velocity’ dynamic amplification mechanism of the guideway-ground structure, and is of relevance to very high speed transport systems such as high speed rail. To demonstrate the new amplification mechanism, first a numerical model is developed, capable of simulating ground-wave propagation in the presence of a series of discrete high speed loads moving on a soil-guideway system. The model couples analytical equations for the transportation system guideway with the thin-layer element method for ground simulation. As a practical example, it is validated using high speed railroad field data and then used to analyse the response of a generalised single moving load at high speed. Next the effect of multiple discrete vehicle-guideway contact points is studied and it is shown that dynamic amplification is highly sensitive to load spacing when the speed is greater than the critical velocity. In particular, large resonant effects occur when the axle/magnet loading frequency and the propagating wave vibration frequency of the soil-guideway structure are equivalent. As an example, it is shown that for an individual case, although critical velocity might increase displacements by 50–100%, for the same scenario, axle configuration can increase displacements by 400%. It is also shown that resonance is sensitive to the total number of loading points and the individual frequencies excited by various spacings. The findings are important for current (e.g. high speed railway) and potential future (e.g. hyperloop) transport systems required to operate at speeds either close-to, or greater than the critical velocity of their supporting guideway-soil structure. In such situations, it is important to design the vehicle and supporting structure(s) as a combined system, rather than in isolation.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2019, Elsevier Ltd. All rights reserved. This is an author produced version of a paper published in Soil Dynamics and Earthquake Engineering. Uploaded in accordance with the publisher's self-archiving policy |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Civil Engineering (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 09 Dec 2019 12:25 |
Last Modified: | 25 Nov 2020 01:40 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.soildyn.2019.105982 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:154317 |