Creep analysis of the rock around engineered barriers

In the study of geological disposal of high level radioactive waste the long-term stability of tunnels constructed in rock is an extremely important factor. Because of the time-dependent properties of rock, creep may have a significant effect on the long-term behavior of the disposal system. This paper first discusses the authors' study of the creep characteristics of rocks. They attempted to theoretically analyze the behavior of the rock after backfilling of the waste forms taking the effect of a multibarrier system into account. The effect of the creep behavior of rock on engineered barriers was analyzed using different parameters to gain an overall view. Because of the idealization of various conditions, theoretical analysis failed to sufficiently clarify certain items. To solve this problem, numerical analysis (FEM analysis) was conducted using a newly developed program. The numerical analysis revealed no adverse effect from the creep behavior of rock on engineered barriers after backfilling of the waste forms