Thermal hydraulic mechanical coupled simulation of FEBEX

Takayama, Yusuke

no journal, , 

It is important to know the state of the barrier at the end of the transient period, in particular the degree of density homogeneity achieved at that stage. In this study, the validity of the existing coupling model is examined focusing, among other things, on the density heterogeneity by applying to the in situ Full-scale Engineered Barrier Experiment (FEBEX) in Grimsel. It was confirmed that linear elastic constitutive model with swelling term applied to the existing coupling model underestimates the density change. Instead, mechanical behavior was re-simulated by unsaturated elasto-plastic constitutive model using the changes in degree of saturation as input data. Although no feedback effects of mechanical behavior on hydraulic and thermal behavior were taken into account, two-dimensional stress and density could be reproduced. Further studies might be required, (1) three dimensional effects on deformation and (2) coupling effects between thermal, hydraulic and mechanical behavior in density heterogeneity. The long-term measurement data and sampling data of three-dimensional spatial distribution of FEBEX and other in-situ tests could also contribute to these further model studies.