Fully coupled THM constitutive model for clay rocks:Formulation and application to laboratory tests  

作　　者：Fei Song Antonio Gens Stefano Collico Dragan Grgic Huaning Wang 

机构地区：[1]School of Aerospace Engineering and Applied Mechanics,Tongji University,Shanghai,200092,China [2]Department of Civil and Environmental Engineering,Universitat Politècnica de Catalunya(UPC),Barcelona,08034,Spain [3]DMT GmbH&Co.KG.,Essen,45307,Germany [4]GeoRessources Laboratory,National School of Geology(ENSG),University of Lorraine,Vandoeuvre-lès-Nancy,54500,France

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2025年第4期1941-1960,共20页岩石力学与岩土工程学报(英文)

基　　金：funded by the European Union's Horizon 2020 research and innovation programme under a grant agreement (Grant No.847593);partially supported by the Fundamental Research Funds for the Central Universities (Grant No.22120240029).

摘　　要：This study presents a fully coupled thermo-hydro-mechanical (THM) constitutive model for clay rocks. The model is formulated within the elastic-viscoplasticity framework, which considers nonlinearity and softening after peak strength, anisotropy of stiffness and strength, as well as permeability variation due to damage. In addition, the mechanical properties are coupled with thermal phenomena and accumulated plastic strains. The adopted nonlocal and viscoplastic approaches enhance numerical efficiency and provide the possibility to simulate localization phenomena. The model is validated against experimental data from laboratory tests conducted on Callovo-Oxfordian (COx) claystone samples that are initially unsaturated and under suction. The tests include a thermal phase where the COx specimens are subjected to different temperature increases. A good agreement with experimental data is obtained. In addition, parametric analyses are carried out to investigate the influence of the hydraulic boundary conditions (B.C.) and post-failure behavior models on the THM behavior evolution. It is shown that different drainage conditions affect the thermally induced pore pressures that, in turn, influence the onset of softening. The constitutive model presented constitutes a promising approach for simulating the most important features of the THM behavior of clay rocks. It is a tool with a high potential for application to several relevant case studies, such as thermal fracturing analysis of nuclear waste disposal systems.

关 键 词：Hard soil Soft rocks Unsaturated/saturated conditions THM coupling processes Thermal pressurization Constitutive model 

分 类 号：TU43[建筑科学—岩土工程] TU45[建筑科学—土工工程]