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Title: Constitutive relationships for elastic deformation of clay rock: Data Analysis

Abstract

Geological repositories have been considered a feasible option worldwide for storing high-level nuclear waste. Clay rock is one of the rock types under consideration for such purposes, because of its favorable features to prevent radionuclide transport from the repository. Coupled hydromechanical processes have an important impact on the performance of a clay repository, and establishing constitutive relationships for modeling such processes are essential. In this study, we propose several constitutive relationships for elastic deformation in indurated clay rocks based on three recently developed concepts. First, when applying Hooke's law in clay rocks, true strain (rock volume change divided by the current rock volume), rather than engineering strain (rock volume change divided by unstressed rock volume), should be used, except when the degree of deformation is very small. In the latter case, the two strains will be practically identical. Second, because of its inherent heterogeneity, clay rock can be divided into two parts, a hard part and a soft part, with the hard part subject to a relatively small degree of deformation compared with the soft part. Third, for swelling rock like clay, effective stress needs to be generalized to include an additional term resulting from the swelling process. To evaluatemore » our theoretical development, we analyze uniaxial test data for core samples of Opalinus clay and laboratory measurements of single fractures within macro-cracked Callovo-Oxfordian argillite samples subject to both confinement and water reduced swelling. The results from this evaluation indicate that our constitutive relationships can adequately represent the data and explain the related observations.« less

Authors:
; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Earth Sciences Division
OSTI Identifier:
1048273
Report Number(s):
LBNL-4903E
Journal ID: ISSN 0723-2632; TRN: US1204156
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Rock Mechanics and Rock Engineering (Austria); Journal Volume: 44; Journal Issue: 4; Related Information: Journal Publication Date: 2011
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; ARGILLITE; CLAYS; CONFINEMENT; DATA ANALYSIS; DEFORMATION; EVALUATION; FRACTURES; OPALINUS CLAY; PERFORMANCE; RADIOACTIVE WASTES; RADIOISOTOPES; SIMULATION; STRAINS; SWELLING; TRANSPORT; WATER

Citation Formats

Liu, H.H., Rutqvist, J., and Birkholzer, J.T. Constitutive relationships for elastic deformation of clay rock: Data Analysis. United States: N. p., 2011. Web. doi:10.1007/s00603-010-0131-4.
Liu, H.H., Rutqvist, J., & Birkholzer, J.T. Constitutive relationships for elastic deformation of clay rock: Data Analysis. United States. doi:10.1007/s00603-010-0131-4.
Liu, H.H., Rutqvist, J., and Birkholzer, J.T. Fri . "Constitutive relationships for elastic deformation of clay rock: Data Analysis". United States. doi:10.1007/s00603-010-0131-4. https://www.osti.gov/servlets/purl/1048273.
@article{osti_1048273,
title = {Constitutive relationships for elastic deformation of clay rock: Data Analysis},
author = {Liu, H.H. and Rutqvist, J. and Birkholzer, J.T.},
abstractNote = {Geological repositories have been considered a feasible option worldwide for storing high-level nuclear waste. Clay rock is one of the rock types under consideration for such purposes, because of its favorable features to prevent radionuclide transport from the repository. Coupled hydromechanical processes have an important impact on the performance of a clay repository, and establishing constitutive relationships for modeling such processes are essential. In this study, we propose several constitutive relationships for elastic deformation in indurated clay rocks based on three recently developed concepts. First, when applying Hooke's law in clay rocks, true strain (rock volume change divided by the current rock volume), rather than engineering strain (rock volume change divided by unstressed rock volume), should be used, except when the degree of deformation is very small. In the latter case, the two strains will be practically identical. Second, because of its inherent heterogeneity, clay rock can be divided into two parts, a hard part and a soft part, with the hard part subject to a relatively small degree of deformation compared with the soft part. Third, for swelling rock like clay, effective stress needs to be generalized to include an additional term resulting from the swelling process. To evaluate our theoretical development, we analyze uniaxial test data for core samples of Opalinus clay and laboratory measurements of single fractures within macro-cracked Callovo-Oxfordian argillite samples subject to both confinement and water reduced swelling. The results from this evaluation indicate that our constitutive relationships can adequately represent the data and explain the related observations.},
doi = {10.1007/s00603-010-0131-4},
journal = {Rock Mechanics and Rock Engineering (Austria)},
number = 4,
volume = 44,
place = {United States},
year = {Fri Apr 15 00:00:00 EDT 2011},
month = {Fri Apr 15 00:00:00 EDT 2011}
}