Quasi-Static State of Thermally Induced Pore Water Pressure

Different forms of thermo-active structures have been proposed as a way of making use of the ground temperature to achieve renewable low-carbon heating and cooling in civil engineering construction. Such structures comprise piles, retaining walls or tunnel linings, and are used both as structural components and as conduits for utilising geothermal energy. In the scenario of the underground space in London, it is the thermo-active piles that have received most attention. However, little experimental evidence exists on the thermal behaviour of London clay to aid the design of thermo-active structures. This paper presents advanced laboratory testing on the reconstituted London clay to characterise the effect of temperature on its mechanical behaviour. Particular emphasis is given to thermally induced pore water pressures, as their evolution is not well understood. Tests are conducted in a temperature-controlled isotropic cell developed at Imperial College London. The emphasis of the current paper is on the temperature-based calibrations of different transducers. Soil specimens are isotropically consolidated and then subjected to undrained heating-cooling in the temperature range of 21 to 37 °C. Results obtained are compared with an existing laboratory study on another type of clay.

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Changes in shaft resistance and pore water pressures during heating of an energy foundation

E3S Web of Conferences ◽

10.1051/e3sconf/202020505022 ◽

2020 ◽

Vol 205 ◽

pp. 05022

Author(s):

Michael B. Reiter ◽

Lydia Kurtz ◽

Mohammed M. Attala ◽

Tugce Baser

Keyword(s):

Hydraulic Conductivity ◽

Pore Water ◽

Mechanical Response ◽

Pore Water Pressure ◽

Water Pressure ◽

Thermally Induced ◽

Shaft Resistance ◽

Pore Water Pressures ◽

Energy Foundations ◽

Surrounding Soil

This study focuses on the evolution of shaft resistance during operation of a geothermal energy foundation installed in a saturated glacial till layer. Energy foundations are a sustainable alternative to traditional space heating and cooling approaches for buildings. Despite efficient operational performance, there are still valid concerns regarding the effects of heating on the structural performance of foundations. To investigate the effect of heating at the soil-pile interface, four drilled shafts are utilized as energy foundations on the Urbana-Champaign campus of the University of Illinois and instrumented. Although the energy foundations are not yet operational, a theoretical investigation is possible to understand the effects of heating on the evolution of thermally induced pore water pressures and the shaft resistance of an energy foundation. A thermo-poroelastic numerical model is validated against an analytical solution, then is used to analyze the thermo-mechanical response of the soil-structure system under different conditions. The results indicate that the evolution of pore water pressure is affected by the rate of heating and the hydraulic conductivity of the surrounding soil, as expected. Higher pore water pressures are generated in the case of low hydraulic conductivity and higher rates of heating. Prior to the dissipation of excess pore pressures, the changes in shaft resistance are variable and influenced by the thermally-induced deformation of the foundation and the surrounding soil.

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Thermally induced volume change and excess pore water pressure of soft Bangkok clay

Engineering Geology ◽

10.1016/j.enggeo.2006.10.002 ◽

2007 ◽

Vol 89 (1-2) ◽

pp. 144-154 ◽

Cited By ~ 79

Author(s):

Hossam M. Abuel-Naga ◽

Dennes T. Bergado ◽

Abdelmalek Bouazza

Keyword(s):

Pore Water ◽

Volume Change ◽

Pore Water Pressure ◽

Water Pressure ◽

Thermally Induced ◽

Excess Pore Water Pressure ◽

Excess Pore

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Measurement of thermally-induced pore-water pressure increase and gas migration in the Opalinus Clay at Mont Terri

Physics and Chemistry of the Earth Parts A/B/C ◽

10.1016/j.pce.2006.04.036 ◽

2007 ◽

Vol 32 (8-14) ◽

pp. 937-946 ◽

Cited By ~ 9

Author(s):

Herbert Kull ◽

Norbert Jockwer ◽

Chun-Liang Zhang ◽

Yannick Wileveau ◽

Stéphane Pepa

Keyword(s):

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Pressure Increase ◽

Opalinus Clay ◽

Gas Migration ◽

Thermally Induced ◽

Mont Terri

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TIME TO THE END OF PRIMARY CONSOLIDATION (EOP) OF SOFT CLAYEY SOILS: CONCERNING THE EFFECT OF ATTERBERG’S LIMIT AND CYCLIC LOADING HISTORY

HUE UNIVERSITY JOURNAL OF SCIENCE TECHNIQUES AND TECHNOLOGY ◽

10.26459/hueuni-jtt.v128i2b.5424 ◽

2019 ◽

Vol 128 (2B) ◽

pp. 29-41

Author(s):

Trần Thanh Nhàn

Keyword(s):

Cyclic Loading ◽

Pore Water ◽

Pore Water Pressure ◽

Water Pressure ◽

Clayey Soils ◽

Loading History ◽

Cyclic Shear ◽

Wide Range ◽

Primary Consolidation ◽

Time Required

In order to observe the end of primary consolidation (EOP) of cohesive soils with and without subjecting to cyclic loading, reconstituted specimens of clayey soils at various Atterberg’s limits were used for oedometer test at different loading increments and undrained cyclic shear test followed by drainage with various cyclic shear directions and a wide range of shear strain amplitudes. The pore water pressure and settlement of the soils were measured with time and the time to EOP was then determined by different methods. It is shown from observed results that the time to EOP determined by 3-t method agrees well with the time required for full dissipation of the pore water pressure and being considerably larger than those determined by Log Time method. These observations were then further evaluated in connection with effects of the Atterberg’s limit and the cyclic loading history.

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Conjectures, Hypotheses, and Theories of Drumlin Formation (In memory of Stanislaw Baranowski)

Journal of Glaciology ◽

10.3189/s0022143000011552 ◽

1981 ◽

Vol 27 (97) ◽

pp. 503-505 ◽

Cited By ~ 1

Author(s):

Ian J. Smalley

Keyword(s):

Shear Strength ◽

Pore Water ◽

Stress Level ◽

Critical Stress ◽

Pore Water Pressure ◽

Water Pressure ◽

Glacial Till ◽

Forming Process ◽

Stress Levels

AbstractRecent investigations have shown that various factors may affect the shear strength of glacial till and that these factors may be involved in the drumlin-forming process. The presence of frozen till in the deforming zone, variation in pore-water pressure in the till, and the occurrence of random patches of dense stony-till texture have been considered. The occurrence of dense stony till may relate to the dilatancy hypothesis and can be considered a likely drumlin-forming factor within the region of critical stress levels. The up-glacier stress level now appears to be the more important, and to provide a sharper division between drumlin-forming and non-drumlin-forming conditions.

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