Simulation of dilatancy-controlled gas migration processes in saturated bentonite using a coupled multiphase flow and elastoplastic H2M model

Publikation: Beitrag in FachzeitschriftForschungsartikelBeigetragenBegutachtung

Beitragende

  • Eike Radeisen - , Federal Institute for Geosciences and Natural Resources (Autor:in)
  • Hua Shao - , Federal Institute for Geosciences and Natural Resources (Autor:in)
  • Jürgen Hesser - , Federal Institute for Geosciences and Natural Resources (Autor:in)
  • Olaf Kolditz - , Professur für Angewandte Umweltsystemanalyse (gB/UFZ), Helmholtz-Zentrum für Umweltforschung (UFZ) (Autor:in)
  • Wenjie Xu - , Zhejiang University (Autor:in)
  • Wenqing Wang - , Helmholtz-Zentrum für Umweltforschung (UFZ) (Autor:in)

Abstract

Dilatancy-controlled gas flow in preferential pathways plays a key role in the safety analysis of radioactive waste repositories. This is particularly the case for bentonite, an often-preferred barrier material. Gas flow in preferential pathways is characterized by localization and spontaneous behavior, which is challenging to simulate in numerical models due to strong hydro-mechanical coupling. To analyze a laboratory experiment in the framework of the DECOVALEX-2023 project, this study introduced a new approach of combining continuous modelling methods with spatial material properties derived from material heterogeneities and experimental observations. The proposed model utilized hydro-mechanical spatial distributions, namely Young's modulus and gas entry pressure, and elastoplasticity combined with a linear swelling model. A conceptual strain-dependent permeability approach simulated dilatancy-controlled gas flow based on hydro-mechanical coupling. To test the effectiveness of the presented approach, a gas injection test in a compacted, saturated bentonite sample was simulated using the open-source code OpenGeoSys 5.8 and compared with experimental observations. The presented methodology is capable of simulating localized gas flow in preferential pathways. The spatial distributions of Young's modulus and gas entry pressure affect the swelling pressure, relative permeability and, in combination with the strain-dependent permeability model, also the intrinsic permeability.

Details

OriginalspracheEnglisch
Seiten (von - bis)803-813
Seitenumfang11
Fachzeitschrift Journal of rock mechanics and geotechnical engineering : JRMGE
Jahrgang15
Ausgabenummer4
PublikationsstatusVeröffentlicht - Apr. 2023
Peer-Review-StatusJa

Schlagworte

ASJC Scopus Sachgebiete

Schlagwörter

  • Continuous approach, Dilatancy-controlled flow, Gas migration, Geomaterial heterogeneity, HM coupling, OpenGeoSys