Geotechnical controls on erodibility in fluvial impact erosion
<p>Bedrock incision by rivers is commonly driven by the impacts of moving bedload particles. The speed of incision is modulated by rock properties, which is quantified within a parameter known as erodibility that scales the erosion rate to the erosive action of the flow. Although basic models...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-10-01
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| Series: | Earth Surface Dynamics |
| Online Access: | https://esurf.copernicus.org/articles/11/979/2023/esurf-11-979-2023.pdf |
| _version_ | 1797663276271665152 |
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| author | J. M. Turowski G. Pruß A. Voigtländer A. Ludwig A. Landgraf F. Kober A. Bonnelye A. Bonnelye |
| author_facet | J. M. Turowski G. Pruß A. Voigtländer A. Ludwig A. Landgraf F. Kober A. Bonnelye A. Bonnelye |
| author_sort | J. M. Turowski |
| collection | DOAJ |
| description | <p>Bedrock incision by rivers is commonly driven by the
impacts of moving bedload particles. The speed of incision is modulated by
rock properties, which is quantified within a parameter known as erodibility
that scales the erosion rate to the erosive action of the flow. Although
basic models for the geotechnical controls on rock erodibility have been
suggested, large scatter and trends in the remaining relationships indicate
that they are incompletely understood. Here, we conducted dedicated
laboratory experiments measuring erodibility using erosion mills. In
parallel, we measured uniaxial compressive strength, tensile strength,
Young's modulus, bulk density, and the Poisson's ratio for the tested
lithologies. We find that under the same flow conditions, erosion rates of
samples from the same lithology can vary by a factor of up to 60. This
indicates that rock properties that may vary over short distances within the
same rock can exert a strong control on its erosional properties. The
geotechnical properties of the tested lithologies are strongly
cross-correlated, preventing a purely empirical determination of their
controls on erodibility. The currently prevailing model predicts that
erosion rates should scale linearly with Young's modulus and inversely with
the square of the tensile strength. We extend this model using
first-principle physical arguments, taking into account the geotechnical
properties of the impactor. The extended model provides a better description
of the data than the existing model. Yet, the fit is far from satisfactory.
We suggest that the ratio of mineral grain size to the impactor diameter
presents a strong control on erodibility that has not been quantified so
far. We also discuss how our laboratory results upscale to real landscapes
and long timescales. For both a revised stream power incision model and a
sediment-flux-dependent incision model, we suggest that long-term erosion
rates scale linearly with erodibility and that, within this theoretical
framework, relative laboratory measurements of erodibility can be applied at
the landscape scale.</p> |
| first_indexed | 2024-03-11T19:12:09Z |
| format | Article |
| id | doaj.art-71871c1a2c03443d98c215e5d71099a2 |
| institution | Directory Open Access Journal |
| issn | 2196-6311 2196-632X |
| language | English |
| last_indexed | 2024-03-11T19:12:09Z |
| publishDate | 2023-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Earth Surface Dynamics |
| spelling | doaj.art-71871c1a2c03443d98c215e5d71099a22023-10-09T11:42:19ZengCopernicus PublicationsEarth Surface Dynamics2196-63112196-632X2023-10-011197999410.5194/esurf-11-979-2023Geotechnical controls on erodibility in fluvial impact erosionJ. M. Turowski0G. Pruß1A. Voigtländer2A. Ludwig3A. Landgraf4F. Kober5A. Bonnelye6A. Bonnelye7Helmholtzzentrum Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, GermanyHelmholtzzentrum Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, GermanyHelmholtzzentrum Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, GermanyNationale Genossenschaft für die Lagerung Radioaktiver Abfälle (NAGRA), 5430 Wettingen, SwitzerlandNationale Genossenschaft für die Lagerung Radioaktiver Abfälle (NAGRA), 5430 Wettingen, SwitzerlandNationale Genossenschaft für die Lagerung Radioaktiver Abfälle (NAGRA), 5430 Wettingen, SwitzerlandHelmholtzzentrum Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, GermanyDépartement Geosciences & Genie Civil, University of Lorraine, Nancy, France<p>Bedrock incision by rivers is commonly driven by the impacts of moving bedload particles. The speed of incision is modulated by rock properties, which is quantified within a parameter known as erodibility that scales the erosion rate to the erosive action of the flow. Although basic models for the geotechnical controls on rock erodibility have been suggested, large scatter and trends in the remaining relationships indicate that they are incompletely understood. Here, we conducted dedicated laboratory experiments measuring erodibility using erosion mills. In parallel, we measured uniaxial compressive strength, tensile strength, Young's modulus, bulk density, and the Poisson's ratio for the tested lithologies. We find that under the same flow conditions, erosion rates of samples from the same lithology can vary by a factor of up to 60. This indicates that rock properties that may vary over short distances within the same rock can exert a strong control on its erosional properties. The geotechnical properties of the tested lithologies are strongly cross-correlated, preventing a purely empirical determination of their controls on erodibility. The currently prevailing model predicts that erosion rates should scale linearly with Young's modulus and inversely with the square of the tensile strength. We extend this model using first-principle physical arguments, taking into account the geotechnical properties of the impactor. The extended model provides a better description of the data than the existing model. Yet, the fit is far from satisfactory. We suggest that the ratio of mineral grain size to the impactor diameter presents a strong control on erodibility that has not been quantified so far. We also discuss how our laboratory results upscale to real landscapes and long timescales. For both a revised stream power incision model and a sediment-flux-dependent incision model, we suggest that long-term erosion rates scale linearly with erodibility and that, within this theoretical framework, relative laboratory measurements of erodibility can be applied at the landscape scale.</p>https://esurf.copernicus.org/articles/11/979/2023/esurf-11-979-2023.pdf |
| spellingShingle | J. M. Turowski G. Pruß A. Voigtländer A. Ludwig A. Landgraf F. Kober A. Bonnelye A. Bonnelye Geotechnical controls on erodibility in fluvial impact erosion Earth Surface Dynamics |
| title | Geotechnical controls on erodibility in fluvial impact erosion |
| title_full | Geotechnical controls on erodibility in fluvial impact erosion |
| title_fullStr | Geotechnical controls on erodibility in fluvial impact erosion |
| title_full_unstemmed | Geotechnical controls on erodibility in fluvial impact erosion |
| title_short | Geotechnical controls on erodibility in fluvial impact erosion |
| title_sort | geotechnical controls on erodibility in fluvial impact erosion |
| url | https://esurf.copernicus.org/articles/11/979/2023/esurf-11-979-2023.pdf |
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