EGU21-7823, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-7823
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Does a Staggered Scheme Pay Off on Large-scale Hydraulic-mechanical Simulations?

Dominik Kern1, Fabien Magri2,3, Victor Malkovsky4, and Thomas Nagel1,5
Dominik Kern et al.
  • 1Institute for Geotechnics, TU Bergakademie Freiberg, Freiberg, Germany (dominik.kern1@ifgt.tu-freiberg.de)
  • 2Division Task-related Research, Federal Office for the Safety of Nuclear Waste Management, Berlin, Germany
  • 3Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
  • 4Institute of Geology of Ore Deposits and Petrography and Mineralogy and Geochemistry, Russian Academy of Sciences, Moscow, Russia
  • 5TUBAF-UFZ Center for Environmental Geosciences, Bergakademie Freiberg, Freiberg, Germany

From previous studies it is evident that decoupled simulations lack the ability to capture certain coupled effects, such as the Noordbergum effect or the Mandel-Cryer effect in a hydraulic-mechanical context. Thus, for detailed simulations of geotechnical or geological system, coupled simulations are usually chosen. For example, thermal-hydraulic-mechanical (THM) coupled systems, and even chemical and biological couplings (THMCB), are considered in simulations used to assess barrier integrity over long time spans in the context of geological waste disposal.

This paper is restricted to coupled hydraulic-mechanical (HM) systems. A monolithic approach is both stable and accurate for strongly coupled systems. However, as site-scale models of geological disposal facilities are also large in spatial dimensions, it is worth to investigate how staggered methods may cut down the computational costs. The fixed-stress split appears to be a promising approach for staggered schemes in terms of stability, consistency, accuracy, and efficiency.

While adding another iteration level in comparison to monolithic schemes, staggered schemes allow for lower-order approximation spaces, whereas monolithic schemes require Taylor-Hood elements resulting in a larger number of degrees of freedom per element. Both coupling schemes are implemented in the the open-source finite-element (FE) software OpenGeoSys and used to simulate a large-scale model, which is oriented towards a real site in planning in Russia. Simulation results are compared in terms of accuracy, coupling effects and performance.

How to cite: Kern, D., Magri, F., Malkovsky, V., and Nagel, T.: Does a Staggered Scheme Pay Off on Large-scale Hydraulic-mechanical Simulations?, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7823, https://doi.org/10.5194/egusphere-egu21-7823, 2021.

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