Modification of thermo-elasto-viscoplastic model for soft rock and its application to THM analysis of heating tests

摘要: In deep geological disposal for high level radioactive waste, one of the most important factors is to study thermo-hydraulic-mechanical (THM) behavior natural barrier, usually a host rock, during heat process and hydraulic environment change. this paper, thermo-elasto-viscoplastic model proposed by Zhang (2009) firstly modified adopting tij concept (Nakai Mihara, 1984) so that influence intermediate stress can be properly considered. The performance confirmed with drained triaxial compression tests creep on soft sedimentary rock manmade under different temperatures. Based model, program called ‘SOFT’, using finite element method (FEM) difference (FDM) in soil–water–heat coupling problem, has been developed simulate aforementioned THM materials. order verify applicability program, an isotropic heating test condition initial overconsolidation ratio (OCR), simulated FE-FD program. test, thermal volumetric change was found dependent OCR. results show phenomenon observed laboratory explained numerical method. Meanwhile, real-scale field reported Gens et al. (2007) also same material parameters involved constitutive are determined based laboratory. It shown agreed well such as time temperature, excess pore water pressure (EPWP) heat-induced strain.