A Study of mechanical effect of simulated fault movement on engineered barrier system

Nishimura, Mayuka; Hirai, Takashi*; Tanai, Kenji ; Yui, Mikazu

The objective of this study is to clarify mechanical effect of engineered barrier system to a fault movement presupposed to occur on geological disposal of high-level radioactive waste. The plan of this study is; (1) to understand mechanical behavior of buffer when shearing takes place in laboratory simulated tests, and (2) to make progress in numerical analysis techniques in order to estimate the effect of fault movement on engineered barrier system on disposal site. Accordingly, first, laboratory simulated tests were carried out with a 1:20 model of engineered barrier system. The experimental results represented that the increased total pressure was mainly due to the increase of pore water pressure. Secondly, the model test was simulated with the help of the finite element method. The calculation results showed that the degree of water draining from buffer into outside affected on the behavior of the pressure increase. It also showed the calculation expressed the experimental results roughly with a proper parameter of permeability of buffer surrounding material.