An evaluation of strain softening of glacial tills as a result of pore pressure dynamics

Ruth Harley, Laura Carse, Kaine Lynch, David Hughes, S. Lee Barbour

In the proceedings of: GeoMontréal 2013: 66th Canadian Geotechnical Conference; 11th joint with IAH-CNC

Session: Landslides I

ABSTRACT: Deep-seated progressive failures of cuttings in heavily overconsolidated clays have been observed in the field and are well documented, especially for London Clays (Potts, Kovacevic, & Vaughan, 1997; Smethurst, Powrie, & Clarke, 2006; Take, 2003), however, the process of softening and the development of a rupture surface in other clays, including the clay fraction of glacial tills, is still to be established. Recent decades have witnessed extreme weather conditions in Northern Ireland with dry summers and wet winters. The dynamics of this pore pressure variation can trigger strength reduction and progressive plastic straining, both of which will lead to slope failure. The aim of this research is to evaluate the effect of pore pressure variations on the deformation and long-term stability of large cuttings in glacial tills in Northern Ireland. This paper outlines the overall research program and presents initial laboratory findings (Carse, 2013).

RÉSUMÉ: Des ruptures progressives et profondes dans des argiles lourdes surconsolidés ont été observées dans le site et ont bien documentées, en particulier pour les argiles de Londres (Potts, Kovacevic, et Vaughan, 1997; Smethurst, Powrie, & Clarke, 2006; Take, 2003), cependant, le processus de ramollissement et le développement d'une surface de rupture dans d'autres argiles, y compris la fraction argileuse des tills glaciaires, doivent être établis. Les dernières décennies ont été marquées par des conditions climatiques extremes en Irelande du Nord, avec des étés secs et des hivers humides. La dynamique de cette variation de la pression interstitielle peuvent déclencher la réduction des forces et des paliers plastiques progressives, conduira à une rupture de la pente. Le but de cette recherche est d'évaluer l'effet des variations de pression interstitielle sur la déformation et la stabilité à long terme de grandes coupes dans les tills glaciaires en Irlande du Nord. Ce document présente l'ensemble du programme de recherche et présente les résultats de laboratoire initiales (Carse, 2013).

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Cite this article:
Ruth Harley; Laura Carse; Kaine Lynch; David Hughes; S. Lee Barbour (2013) An evaluation of strain softening of glacial tills as a result of pore pressure dynamics in GEO2013. Ottawa, Ontario: Canadian Geotechnical Society.

@article{GeoMon2013Paper354,author = Ruth Harley; Laura Carse; Kaine Lynch; David Hughes; S. Lee Barbour,title = An evaluation of strain softening of glacial tills as a result of pore pressure dynamics ,year = 2013}