Development of mechanical coupled analysis technique for the long term behavior of the near field (2)

In evaluating the long term mechanical behavior of the near field containing Engineered Barrier System (EBS), it is essential to take into consideration the behaviors which affect the stress and deformation of the buffer material. The 3-D mechanical coupled analysis technique for the long term mechanical behavior of near field is developed. The object of analysis is extended to the disposal gallery and the near field rock, in addition to the buffer material and the overpack for previous one. The analysis model is developed with a degradation model of concrete support and modeling of the near field rock with the valuable- compliance-type constitutive equation. The remaining problems of current study are related to; 1) mechanical property and modeling of backfill material, 2) adopting a degradation model of concrete support in the prototype model, 3) examining the effect of analytical model mesh and time step for the 3-D mechanical coupled analysis. We conducted the one-dimensional consolidation test for the backfill material. The backfill material shows a similar behavior to that of buffer material. And the prototype model is developed adopting a degradation model for a concrete support and examining the effect of the model mesh and time step. The result shows that a degradation of concrete support affects the mechanical behavior of the near field. It is concluded this analysis technique is promising for evaluation of the long term mechanical behavior of the near field. (author)