Research on evaluation of coupled thermo-hydro-mechanical behavior in the engineered barrier

Chijimatsu, Masakazu*; Amemiya, Kiyoshi*; Yamashita, Ryo*

After emplacement of the engineered barrier system (EBS), it is expected that the near-field environment will be impacted by phenomena such as heat dissipation by conduction and other heat transter mechanisms, infiltration of groundwater from the surrounding rock in to the engineered barrier system, stress imposed by the overburden pressure and generation of swelling pressure in the buffer due to water infiltation. In order to recognize and evaluate these coupled thermo-hydro-mechanical (THM) phenomena, it is necessary to make a confidence of the mathematical model and computer codes. Evaluating these coupled THM phenomena is important in order to clarify the initial transient behavior of the EBS within the near field. DECOVALEX project is an international co-opelative project for the DEvelopment of COupled models and their VALidation against EXperiments in nuclear waste isolation and it is significance to participate this project and to apply the code for the validation. Therefore, we tried to apply the developed numerical code against the subjects of DECOVALEX. In the above numerical code, swelling phenomenon is modeled as the function of water potential. However it does not evaluate the experiment results enough. Then, we try to apply the new model.