Finite element analyses of an inhomogeneous bentonite barrier for geological radioactive waste disposal applications
Finite element analyses of an inhomogeneous bentonite barrier for geological radioactive waste disposal applications
Engineered barriers employed in geological radioactive waste repositories are usually formed of compacted unsaturated bentonite blocks, often used together with bentonite pellets. Compacted bentonite blocks have very low permeabilities, hence their saturation can take hundreds of years. Predicting the bentonite behaviour over such a long time frame is challenging, given that representative laboratory or field experiments over a similar time are unfeasible. In this scenario, numerical tools enable predictive assessments of the long-term barrier performance. The paper reports the results of hydro-mechanically coupled Finite Element (FE) analyses conducted to assess the long-term response of the KBS-3 design scheme developed in Sweden by SKB. Two 2D axisymmetric FE analyses were conducted, simulating two different barrier saturation scenarios, i.e. fast and slow hydration. The simulations were conducted with the code ICFEP, using a constitutive model capable of reproducing the hydro-mechanical behaviour of unsaturated expansive soils with a dual-porosity structure. The analyses verified the long-term safety requirements of the inhomogeneous block-and-pellet bentonite barrier adopted in the KBS-3 scheme.
Giuseppe Pedone; Lidija Zdravkovic; David Malcolm Potts; Aikaterini Tsiampousi
10th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE2023)
13. Geo-energy & energy geotechnics
https://doi.org/10.53243/NUMGE2023-149
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