The University of Southampton
University of Southampton Institutional Repository

In situ sensing guided geotechnical modelling of subglacial deformation

In situ sensing guided geotechnical modelling of subglacial deformation
In situ sensing guided geotechnical modelling of subglacial deformation
Data collected by in situ subglacial probes has been used to guide a series of geotechnical tests on till. The testing provides an opportunity to develop a process-based understanding of movement patterns observed in the subglacial environment. The probes were deployed by the Glacsweb project at Skalafellsjökull, Iceland, in 2008 and 2012. They were emplaced in till below 80 m of ice and recorded a number of variables including pore pressure, case stress, movement and conductivity. During the winter of 2008-2009 cyclic pressure changes were recorded in the till. Repeated pore pressure increases of up to 20% occurred over a variable period of one to eight weeks. Each rise was followed by a sharp drop in pore pressure lasting up to a few days. A back pressure shear box was used to replicate the pore pressure changes whilst maintaining a constant horizontal shear stress and normal total stress to examine effects on deformation and strain rate. Till was collected for testing from the ice margin close to the probes in 2012 and remoulded for use in the back pressure shear box. General characterisation of the till was performed to benchmark it against previous work and then a series of pore pressure re-inflation tests were undertaken. These approximated the pore pressure variations observed in the field by linearly increasing pore pressure and so decreasing normal effective stress. The till displayed dilatancy-induced episodic increases in strain rate. These were regulated by consolidation that increased shear strength and so reduced strain rate. Strain rate variations were similar to ice velocity variations recorded by differential GPS deployed on the ice surface above the probes.
Hart, Jane
e949a885-7b26-4544-9e15-32ba6f87e49a
Hart, Jane
e949a885-7b26-4544-9e15-32ba6f87e49a

Hart, Jane (2014) In situ sensing guided geotechnical modelling of subglacial deformation. American Geophysical Union, Fall Meeting 2014, San Francisco, United States. 15 - 19 Dec 2014.

Record type: Conference or Workshop Item (Other)

Abstract

Data collected by in situ subglacial probes has been used to guide a series of geotechnical tests on till. The testing provides an opportunity to develop a process-based understanding of movement patterns observed in the subglacial environment. The probes were deployed by the Glacsweb project at Skalafellsjökull, Iceland, in 2008 and 2012. They were emplaced in till below 80 m of ice and recorded a number of variables including pore pressure, case stress, movement and conductivity. During the winter of 2008-2009 cyclic pressure changes were recorded in the till. Repeated pore pressure increases of up to 20% occurred over a variable period of one to eight weeks. Each rise was followed by a sharp drop in pore pressure lasting up to a few days. A back pressure shear box was used to replicate the pore pressure changes whilst maintaining a constant horizontal shear stress and normal total stress to examine effects on deformation and strain rate. Till was collected for testing from the ice margin close to the probes in 2012 and remoulded for use in the back pressure shear box. General characterisation of the till was performed to benchmark it against previous work and then a series of pore pressure re-inflation tests were undertaken. These approximated the pore pressure variations observed in the field by linearly increasing pore pressure and so decreasing normal effective stress. The till displayed dilatancy-induced episodic increases in strain rate. These were regulated by consolidation that increased shear strength and so reduced strain rate. Strain rate variations were similar to ice velocity variations recorded by differential GPS deployed on the ice surface above the probes.

Full text not available from this repository.

More information

Published date: December 2014
Venue - Dates: American Geophysical Union, Fall Meeting 2014, San Francisco, United States, 2014-12-15 - 2014-12-19

Identifiers

Local EPrints ID: 432536
URI: http://eprints.soton.ac.uk/id/eprint/432536
PURE UUID: ef147b12-5289-4a48-99e5-b19826b06ff5
ORCID for Jane Hart: ORCID iD orcid.org/0000-0002-2348-3944

Catalogue record

Date deposited: 17 Jul 2019 16:30
Last modified: 20 Jul 2019 01:25

Export record

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.

×