D. Entwisle

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David Seamon

Kansas State University

Armando Marques-Guedes

UNL - New University of Lisbon

Dr.Subramaniam Karuppannan

Open University Malaysia (OUM),

Ajit Sarmah

The University of Auckland

Julien G.R. Vincent

Université Paris 1 - Panthéon-Sorbonne

Blanca Figuerola

CSIC (Consejo Superior de Investigaciones Científicas-Spanish National Research Council)

Fernando Ángel Fernández-Álvarez

CSIC (Consejo Superior de Investigaciones Científicas-Spanish National Research Council)

Mohamed Ahmed Youssef

Al-Azhar University

Lewis Peake

University of East Anglia

widiatmaka widiatmaka

Bogor Agricultural University

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Papers by D. Entwisle

Electrical resistivity monitoring of a collapsing meta-stable soil

Quarterly Journal of Engineering Geology and Hydrogeology, 2006

ABSTRACT A model of electrical conduction through clay-coated, silt-sized quartz-grains inter-con... more ABSTRACT A model of electrical conduction through clay-coated, silt-sized quartz-grains inter-connected by clay-bridges (e.g. brickearth) is developed. Underpinned by SEM studies of brickearth, the model predicts resistivity to be proportional to the size of the quartz-grains, where the resistance afforded by clay grain-coatings and clay-bridges is comparable. The model accommodates resistivity that increases through bridge breakage and decreases through bridge compression. The resistivity of in-situ undisturbed brickearth was found to be in the range 15 to 35 ohm-m. At such low values we demonstrate that electrical flow is dominated by conduction within clay-coatings and their interconnecting clay-bridges, rather than in mobile pore-water. A small electrode array, buried at shallow depth beneath the load plate (1.0 m by 1.0 m) of a field collapse experiment, monitored resistivity to a depth of 1.5 m over a 260 hour period. While the water level beneath the load plate remained below 1.0 m depth, the resulting 3D inverted resistivity models detected water injected immediately beneath the plate; recording rapid increases, in stages over 90 minutes, in the depth interval 0.45 to 0.75 m directly under the plate, during what appears to be collapse. These increases are attributed to breaking of clay-bridges weakened by injected water.

Material properties and geohazards

by adrian collings, D. Entwisle, and Martin Culshaw

User guide for the British Geological Survey GeoClimateUKCP09 : clay shrink-swell dataset

This report is the guide for users of the British Geological Survey (BGS) GeoClimateUKCP09 clay s... more This report is the guide for users of the British Geological Survey (BGS) GeoClimateUKCP09 clay shrink-swell dataset. This is a national scale assessment of variations in clay shrink swell susceptibility due to climate change. GeoClimateUKCP09 clay shrink-swell provides information on the potential for clay shrink swell to occur at a given location, during a given future time period, based on a combination of geological, hydrological and climate projection data

D. Entwisle

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