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Titel |
Simulation of rock salt dissolution and its impact on land subsidence |
VerfasserIn |
A. Zidane, E. Zechner, P. Huggenberger, A. Younes |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1027-5606
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Digitales Dokument |
URL |
Erschienen |
In: Hydrology and Earth System Sciences ; 18, no. 6 ; Nr. 18, no. 6 (2014-06-17), S.2177-2189 |
Datensatznummer |
250120383
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Publikation (Nr.) |
copernicus.org/hess-18-2177-2014.pdf |
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Zusammenfassung |
Extensive land subsidence can occur due to subsurface dissolution of
evaporites such as halite and gypsum. This paper explores techniques to
simulate the salt dissolution forming an intrastratal karst, which is
embedded in a sequence of carbonates, marls, anhydrite and gypsum. A
numerical model is developed to simulate laminar flow in a subhorizontal
void, which corresponds to an opening intrastratal karst. The numerical
model is based on the laminar steady-state Stokes flow equation, and the
advection dispersion transport equation coupled with the dissolution
equation. The flow equation is solved using the nonconforming
Crouzeix–Raviart (CR) finite element approximation for the Stokes equation.
For the transport equation, a combination between discontinuous Galerkin
method and multipoint flux approximation method is proposed. The numerical
effect of the dissolution is considered by using a dynamic mesh variation
that increases the size of the mesh based on the amount of dissolved salt.
The numerical method is applied to a 2-D geological cross section
representing a Horst and Graben structure in the Tabular Jura of northwestern
Switzerland. The model simulates salt dissolution within the geological
section and predicts the amount of vertical dissolution as an indicator of
potential subsidence that could occur. Simulation results showed that the
highest dissolution amount is observed near the normal fault zones, and,
therefore, the highest subsidence rates are expected above normal fault
zones. |
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