THM Experiment for the Investigation of Freeze-Thaw Processes in Unconsolidated Rock and Geotechnical Grouts
Technical University of Darmstadt, Geothermal Science and Technology, Darmstadt, Germany (1); Darmstadt Graduate School of Excellence Energy Science and Engineering, Darmstadt, Germany (2); Technische Hochschule Ostwestfalen-Lippe, FB 8, Geotechnics and Geothermal Energy, Höxter, Germany (3) Freezin...
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Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
2020
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ftdatacite:10.48380/dggv-cpwa-n657 2023-05-15T16:37:53+02:00 THM Experiment for the Investigation of Freeze-Thaw Processes in Unconsolidated Rock and Geotechnical Grouts Hesse , 2 Kupfernagel 3, Jan-Henrik Schedel, 2 Welsch , 2 Müller, Lutz Sass, 2 2020 https://dx.doi.org/10.48380/dggv-cpwa-n657 https://www.dggv.de/publikationen/dggv-e-publikationen/publication/66.html en eng Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV) Text Abstract article-journal ScholarlyArticle 2020 ftdatacite https://doi.org/10.48380/dggv-cpwa-n657 2021-11-05T12:55:41Z Technical University of Darmstadt, Geothermal Science and Technology, Darmstadt, Germany (1); Darmstadt Graduate School of Excellence Energy Science and Engineering, Darmstadt, Germany (2); Technische Hochschule Ostwestfalen-Lippe, FB 8, Geotechnics and Geothermal Energy, Höxter, Germany (3) Freezing and thawing in the subsurface is often associated with a complex technical handling of possible influences on the engineered structures (e.g. ground freezing, permafrost, geothermal heat pumps). However, detailed knowledge on freeze-thaw processes in porous media, such as unconsolidated rocks or geotechnical grouts, is still pending. Freezing in porous media does not occur as a sudden transition from pure liquid water to the ice phase, but rather within a freezing interval strongly depending on various boundary conditions such as soil type or pore water chemistry. As the content of frozen and unfrozen water has a strong impact on material properties, it is essential to have adequate information about the different factors influencing freezing processes as well as the thermo-hydraulic-mechanical (THM) effects on porous media due to phase change. Therefore, a THM laboratory experiment was designed and built to gain more detailed knowledge on freeze-thaw processes and their effects in porous media. A modified triaxial test, enabling for a confining pressure up to 1.2 MPa, is linked with an ultrasonic measurement device to determine the unfrozen water content at defined boundary conditions. The confining pressure fluid (water-glycol-mixture) can be tempered via a cooling circuit down to -25 °C. Axial and radial deformation of the specimen are measured as well as further mechanical parameters such as the freeze pressure. Furthermore, the hydraulic conductivity of the sample is determined to investigate the influence of water flow on the freezing process. Text Ice permafrost DataCite Metadata Store (German National Library of Science and Technology) |
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ftdatacite |
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English |
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Technical University of Darmstadt, Geothermal Science and Technology, Darmstadt, Germany (1); Darmstadt Graduate School of Excellence Energy Science and Engineering, Darmstadt, Germany (2); Technische Hochschule Ostwestfalen-Lippe, FB 8, Geotechnics and Geothermal Energy, Höxter, Germany (3) Freezing and thawing in the subsurface is often associated with a complex technical handling of possible influences on the engineered structures (e.g. ground freezing, permafrost, geothermal heat pumps). However, detailed knowledge on freeze-thaw processes in porous media, such as unconsolidated rocks or geotechnical grouts, is still pending. Freezing in porous media does not occur as a sudden transition from pure liquid water to the ice phase, but rather within a freezing interval strongly depending on various boundary conditions such as soil type or pore water chemistry. As the content of frozen and unfrozen water has a strong impact on material properties, it is essential to have adequate information about the different factors influencing freezing processes as well as the thermo-hydraulic-mechanical (THM) effects on porous media due to phase change. Therefore, a THM laboratory experiment was designed and built to gain more detailed knowledge on freeze-thaw processes and their effects in porous media. A modified triaxial test, enabling for a confining pressure up to 1.2 MPa, is linked with an ultrasonic measurement device to determine the unfrozen water content at defined boundary conditions. The confining pressure fluid (water-glycol-mixture) can be tempered via a cooling circuit down to -25 °C. Axial and radial deformation of the specimen are measured as well as further mechanical parameters such as the freeze pressure. Furthermore, the hydraulic conductivity of the sample is determined to investigate the influence of water flow on the freezing process. |
format |
Text |
author |
Hesse , 2 Kupfernagel 3, Jan-Henrik Schedel, 2 Welsch , 2 Müller, Lutz Sass, 2 |
spellingShingle |
Hesse , 2 Kupfernagel 3, Jan-Henrik Schedel, 2 Welsch , 2 Müller, Lutz Sass, 2 THM Experiment for the Investigation of Freeze-Thaw Processes in Unconsolidated Rock and Geotechnical Grouts |
author_facet |
Hesse , 2 Kupfernagel 3, Jan-Henrik Schedel, 2 Welsch , 2 Müller, Lutz Sass, 2 |
author_sort |
Hesse , 2 |
title |
THM Experiment for the Investigation of Freeze-Thaw Processes in Unconsolidated Rock and Geotechnical Grouts |
title_short |
THM Experiment for the Investigation of Freeze-Thaw Processes in Unconsolidated Rock and Geotechnical Grouts |
title_full |
THM Experiment for the Investigation of Freeze-Thaw Processes in Unconsolidated Rock and Geotechnical Grouts |
title_fullStr |
THM Experiment for the Investigation of Freeze-Thaw Processes in Unconsolidated Rock and Geotechnical Grouts |
title_full_unstemmed |
THM Experiment for the Investigation of Freeze-Thaw Processes in Unconsolidated Rock and Geotechnical Grouts |
title_sort |
thm experiment for the investigation of freeze-thaw processes in unconsolidated rock and geotechnical grouts |
publisher |
Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV) |
publishDate |
2020 |
url |
https://dx.doi.org/10.48380/dggv-cpwa-n657 https://www.dggv.de/publikationen/dggv-e-publikationen/publication/66.html |
genre |
Ice permafrost |
genre_facet |
Ice permafrost |
op_doi |
https://doi.org/10.48380/dggv-cpwa-n657 |
_version_ |
1766028189427040256 |