Simulation of dilatancy-controlled gas migration processes in saturated bentonite using a coupled multiphase flow and elastoplastic H2 M model  

作　　者：Eike Radeisen Hua Shao Jürgen Hesser Olaf Kolditz Wenjie Xu Wenqing Wang 

机构地区：[1]Department of Rock Characterization for Storage and Final Disposal,Federal Institute for Geosciences and Natural Resources(BGR),Hannover,30655,Germany [2]Department of Environmental Informatics,Helmholtz Center for Environmental Research(UFZ),Leipzig,04341,Germany [3]Department of Applied Environmental Systems Analysis,Technische Universität Dresden,Dresden,01069,Germany [4]Department of Civil Engineering and Architecture,Zhejiang University,Hangzhou,310058,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2023年第4期803-813,共11页岩石力学与岩土工程学报（英文版）

基　　金：This research was conducted within the DECOVALEX-2023 project;DECOVALEX is an international research project comprising participants from industry,government,and academia,focusing on development of understanding,models and codes in complex coupled problems in sub-surface geological and engineering applications.DECOVALEX-2023 is the current phase of the project.The authors appreciate the DECOVALEX-2023 Funding Organisations Andra,BASE,BGE,BGR,CAS,CNSC,COVRA,US DOE,ENRESA,ENSI,JAEA,KAERI,NWMO,RWM,SÚRAO,SSM and Taipower for their financial and technical support of the work described in this paper.The statements made in the paper are,however,solely those of the authors and do not necessarily reflect those of the Funding Organisations.This work was further supported by the German Federal Ministry for Economic Affairs and Climate Action(BMWK).

摘　　要：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 dilatancycontrolled 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 opensource 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.

关 键 词：H^(2)M coupling Gas migration Dilatancy-controlled flow Continuous approach Geomaterial heterogeneity OPENGEOSYS 

分 类 号：TL942[核科学技术—辐射防护及环境保护] X591[环境科学与工程—环境工程] X141