The University of Southampton
University of Southampton Institutional Repository

Soil parameters for modelling critical velocity effects of railways

Soil parameters for modelling critical velocity effects of railways
Soil parameters for modelling critical velocity effects of railways
In many countries high speed rail is playing a growing role in improving the capacity, availability and carbon cost of national infrastructure. Higher speeds require straighter railway alignments, which often means crossing areas of soft ground that have historically been avoided. Due to their low ground-borne surface wave speeds, there is a greater likelihood in such areas of the train passage resulting in critical velocity effects – a phenomenon in which excessive ground and track movement and vibration occurs. This can cause extensive damage, and may result in a forced reduction of train speeds.

The aim of this research is to assess methods of determining appropriate soil parameters for use in simple elasticity-based models for the prediction of critical velocity effects on railways. After a review of existing knowledge, the research consists of field measurements, laboratory experiments and modelling.

This research focuses around two case study sites on the UK rail network. Soil samples were extracted from each site, and tested in resonant column and triaxial equipment, to investigate their strain-dependent stiffness and damping. This involved testing on soil types for which there is little published data, including highly organic silts. The results are compared with measurements taken in situ, including seismic analysis and heavy probe tests.

A linear elastic model, MOTIV, of train-induced vibration is used to investigate the key soil and model parameters required for critical velocity analysis, as well as to assess the importance of the non-linearity of soil stiffness and damping with strain. It is clear that the use of strain-degraded soil parameters, for example through the use of an equivalent linear model, is essential. Recommendations are made for the best methods to obtain the relevant data, from which reliable critical velocity predictions can be made using linear soil models.
University of Southampton
Duley, Alice
18956f32-f62d-4159-b1ec-0cb1b08b187b
Duley, Alice
18956f32-f62d-4159-b1ec-0cb1b08b187b
Le Pen, Louis
4a38e256-d113-4bba-b0d4-32d41995928a

Duley, Alice (2018) Soil parameters for modelling critical velocity effects of railways. University of Southampton, Doctoral Thesis, 269pp.

Record type: Thesis (Doctoral)

Abstract

In many countries high speed rail is playing a growing role in improving the capacity, availability and carbon cost of national infrastructure. Higher speeds require straighter railway alignments, which often means crossing areas of soft ground that have historically been avoided. Due to their low ground-borne surface wave speeds, there is a greater likelihood in such areas of the train passage resulting in critical velocity effects – a phenomenon in which excessive ground and track movement and vibration occurs. This can cause extensive damage, and may result in a forced reduction of train speeds.

The aim of this research is to assess methods of determining appropriate soil parameters for use in simple elasticity-based models for the prediction of critical velocity effects on railways. After a review of existing knowledge, the research consists of field measurements, laboratory experiments and modelling.

This research focuses around two case study sites on the UK rail network. Soil samples were extracted from each site, and tested in resonant column and triaxial equipment, to investigate their strain-dependent stiffness and damping. This involved testing on soil types for which there is little published data, including highly organic silts. The results are compared with measurements taken in situ, including seismic analysis and heavy probe tests.

A linear elastic model, MOTIV, of train-induced vibration is used to investigate the key soil and model parameters required for critical velocity analysis, as well as to assess the importance of the non-linearity of soil stiffness and damping with strain. It is clear that the use of strain-degraded soil parameters, for example through the use of an equivalent linear model, is essential. Recommendations are made for the best methods to obtain the relevant data, from which reliable critical velocity predictions can be made using linear soil models.

Text
duley-thesis-correctionsv1 - Version of Record
Available under License University of Southampton Thesis Licence.
Download (16MB)

More information

Published date: December 2018

Identifiers

Local EPrints ID: 433347
URI: http://eprints.soton.ac.uk/id/eprint/433347
PURE UUID: a4b22f2f-1057-44f4-bb47-762e9c3ef89a
ORCID for Louis Le Pen: ORCID iD orcid.org/0000-0002-4362-3895

Catalogue record

Date deposited: 14 Aug 2019 16:30
Last modified: 24 Jun 2020 04:01

Export record

Contributors

Author: Alice Duley
Thesis advisor: Louis Le Pen ORCID iD

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×