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The influence of earthworks construction on porewater pressures in clays and mudstones of the Lias Group

The influence of earthworks construction on porewater pressures in clays and mudstones of the Lias Group
The influence of earthworks construction on porewater pressures in clays and mudstones of the Lias Group
Monitoring the changes in pore water pressure associated with the construction of earthworks can yield information on the stiffness and permeability of the ground, as well as how the natural groundwater regime might be impacted. This paper presents three years of pore water pressure measurements in weathered Lias Group mudstone, obtained from a trial cutting and a trial embankment constructed for the UK's High Speed Two (HS2) railway. The immediate changes in pore water pressure were small in relation to the changes in total stress imposed. This can be explained by the consolidation or swelling during the period of construction, combined with the sensitivity of very stiff clays and mudstones to a very small (0.5%) reduction in the degree of saturation. In the longer-term, pore water pressures reduced across the site owing to the reduction in ground level at the trial cutting. Rates of pore water pressure change were accelerated by more permeable limestone within the ground profile reducing drainage path lengths. It is concluded that construction-induced pore water pressure changes may be smaller, and their rate of dissipation more rapid, in weathered clays and mudstones such as those of the Lias Group than in younger, more compressible clay deposits.
1470-9236
Briggs, Kevin M.
8974f7ce-2757-4481-9dbc-07510b416de4
González, Yuderka Trinidad
e54faa6d-0108-4fe2-b706-3cabe8836729
Meijer, Gerrit J.
0d6d3604-d0e3-43eb-afbe-6638ae74c4ce
Ridley, Andrew
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Powrie, William
600c3f02-00f8-4486-ae4b-b4fc8ec77c3c
Butler, Simon
2ac81aeb-4aff-4f90-97e7-69812cc061c4
Sartain, Nick
f11351ef-d9c0-4c08-ac7c-c69846ce1e44
Briggs, Kevin M.
8974f7ce-2757-4481-9dbc-07510b416de4
González, Yuderka Trinidad
e54faa6d-0108-4fe2-b706-3cabe8836729
Meijer, Gerrit J.
0d6d3604-d0e3-43eb-afbe-6638ae74c4ce
Ridley, Andrew
78cea8b3-6d42-476b-b513-121d65b160c4
Powrie, William
600c3f02-00f8-4486-ae4b-b4fc8ec77c3c
Butler, Simon
2ac81aeb-4aff-4f90-97e7-69812cc061c4
Sartain, Nick
f11351ef-d9c0-4c08-ac7c-c69846ce1e44

Briggs, Kevin M., González, Yuderka Trinidad, Meijer, Gerrit J., Ridley, Andrew, Powrie, William, Butler, Simon and Sartain, Nick (2024) The influence of earthworks construction on porewater pressures in clays and mudstones of the Lias Group. Quarterly Journal of Engineering Geology and Hydrogeology, 57 (4), [qjegh2024-036]. (doi:10.1144/qjegh2024-036).

Record type: Article

Abstract

Monitoring the changes in pore water pressure associated with the construction of earthworks can yield information on the stiffness and permeability of the ground, as well as how the natural groundwater regime might be impacted. This paper presents three years of pore water pressure measurements in weathered Lias Group mudstone, obtained from a trial cutting and a trial embankment constructed for the UK's High Speed Two (HS2) railway. The immediate changes in pore water pressure were small in relation to the changes in total stress imposed. This can be explained by the consolidation or swelling during the period of construction, combined with the sensitivity of very stiff clays and mudstones to a very small (0.5%) reduction in the degree of saturation. In the longer-term, pore water pressures reduced across the site owing to the reduction in ground level at the trial cutting. Rates of pore water pressure change were accelerated by more permeable limestone within the ground profile reducing drainage path lengths. It is concluded that construction-induced pore water pressure changes may be smaller, and their rate of dissipation more rapid, in weathered clays and mudstones such as those of the Lias Group than in younger, more compressible clay deposits.

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briggs-et-al-2024-the-influence-of-earthworks-construction-on-pore-water-pressures-in-clays-and-mudstones-of-the-lias - Accepted Manuscript
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More information

Accepted/In Press date: 14 July 2024
e-pub ahead of print date: 22 July 2024
Published date: 16 August 2024

Identifiers

Local EPrints ID: 492199
URI: http://eprints.soton.ac.uk/id/eprint/492199
ISSN: 1470-9236
PURE UUID: d26fac12-0cee-44bf-8dd9-bf56bd92b329
ORCID for Kevin M. Briggs: ORCID iD orcid.org/0000-0003-1738-9692
ORCID for William Powrie: ORCID iD orcid.org/0000-0002-2271-0826

Catalogue record

Date deposited: 22 Jul 2024 16:32
Last modified: 04 Sep 2024 01:42

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Contributors

Author: Kevin M. Briggs ORCID iD
Author: Yuderka Trinidad González
Author: Gerrit J. Meijer
Author: Andrew Ridley
Author: William Powrie ORCID iD
Author: Simon Butler
Author: Nick Sartain

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