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Modeling of excavation induced coupled hydraulic-mechanical processes in claystone

Abstract

Concepts for the numerical modeling of excavation induced processes in claystone are investigated. The study has been motivated by the international discussion on the adequacy of claystone as a potential host rock for a final repository of radioactive waste. The processes, which could impact the safety of such a repository, are manifold and strongly interacting. Thus, a multiphysics approach is needed, regarding solid mechanics and fluid mechanics within a geological context. A coupled modeling concept is therefore indispensable. Based on observations and measurements at an argillaceous test site (the underground laboratory Tournemire, operated by the Institute of Radioprotection and Nuclear Safety, France) the modeling concept is developed. Two main processes constitute the basis of the applied model: deformation (linear elasticity considering damage) and fluid flow (unsaturated one-phase flow). Several coupling phenomena are considered: Terzaghi 's effective stress concept, mass conservation of the liquid in a deformable porous media, drying induced shrinkage, and a permeability which depends on deformation and damage. In addition, transversely isotropic material behavior is considered. The numerical simulations are done with the finite element code RockFlow, which is extended to include: an orthotropic non-linear shrinkage model, a continuum damage model, and an orthotropic permeability model. For these  More>>
Authors:
Publication Date:
Jul 01, 2009
Product Type:
Thesis/Dissertation
Report Number:
INIS-DE-0882
Resource Relation:
Other Information: TH: Diss. (Dr.-Ing.); Related Information: Hannover Universitaet, Institut fuer Grundbau, Bodenmechanik und Energiewasserbau. Mitteilungenv. 66
Subject:
54 ENVIRONMENTAL SCIENCES; 12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; ARGILLITE; CLAYS; DEFORMATION; EXCAVATION; FLUID FLOW; GEOLOGIC FORMATIONS; HYDRAULIC MINING; HYDRAULICS; NUMERICAL ANALYSIS; RADIOACTIVE WASTE FACILITIES; RADIOACTIVE WASTE STORAGE; ROCK MECHANICS; SHRINKAGE; UNDERGROUND FACILITIES
OSTI ID:
21269578
Research Organizations:
Hannover Univ. (Germany). Inst. fuer Grundbau, Bodenmechanik und Energiewasserbau (IGBE); Hannover Univ. (Germany). Fakultaet fuer Bauingenieurwesen und Geodaesie
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
TRN: DE10F1362
Availability:
Available from TIB Hannover; Commercial reproduction prohibited; INIS; OSTI as DE21269578
Submitting Site:
DEN
Size:
195 pages
Announcement Date:
Jun 21, 2010

Citation Formats

Massmann, Jobst. Modeling of excavation induced coupled hydraulic-mechanical processes in claystone. Germany: N. p., 2009. Web.
Massmann, Jobst. Modeling of excavation induced coupled hydraulic-mechanical processes in claystone. Germany.
Massmann, Jobst. 2009. "Modeling of excavation induced coupled hydraulic-mechanical processes in claystone." Germany.
@misc{etde_21269578,
title = {Modeling of excavation induced coupled hydraulic-mechanical processes in claystone}
author = {Massmann, Jobst}
abstractNote = {Concepts for the numerical modeling of excavation induced processes in claystone are investigated. The study has been motivated by the international discussion on the adequacy of claystone as a potential host rock for a final repository of radioactive waste. The processes, which could impact the safety of such a repository, are manifold and strongly interacting. Thus, a multiphysics approach is needed, regarding solid mechanics and fluid mechanics within a geological context. A coupled modeling concept is therefore indispensable. Based on observations and measurements at an argillaceous test site (the underground laboratory Tournemire, operated by the Institute of Radioprotection and Nuclear Safety, France) the modeling concept is developed. Two main processes constitute the basis of the applied model: deformation (linear elasticity considering damage) and fluid flow (unsaturated one-phase flow). Several coupling phenomena are considered: Terzaghi 's effective stress concept, mass conservation of the liquid in a deformable porous media, drying induced shrinkage, and a permeability which depends on deformation and damage. In addition, transversely isotropic material behavior is considered. The numerical simulations are done with the finite element code RockFlow, which is extended to include: an orthotropic non-linear shrinkage model, a continuum damage model, and an orthotropic permeability model. For these new methods the theory and a literature review are presented, followed by applications, which illustrate the capability to model excavation induced processes in principle. In a comprehensive case study, the modeling concept is used to simulate the response of the Tournemire argillite to excavation. The results are compared with observations and measurements of three different excavations (century old tunnel, two galleries excavated in 1996 and 2003). In summary, it can be concluded that the developed model concept provides a prediction of the excavation induced hydraulic and mechanical response for a time period of at least ten years. An explanation can be given for the delayed development of an excavation damaged zone. It is caused by the desaturation induced shrinkage. (orig.)}
place = {Germany}
year = {2009}
month = {Jul}
}