3D modeling of the mechanical behavior of liners (segments) placed around the gallery of nuclear waste repository
Résumé
In 2005, Andra concluded that the feasibility of deep geological repository for high level (HLW) and intermediate level (ILW) long-lived waste was valid. Hence, Andra is now responsible for designing and implementing a repository disposal for HLW and ILW waste called: CIGEO (Geological Repository Project). A zone of interest for thorough exploration (ZIRA) was suggested in 2009. A simulation program is included to the CIGEO project. One of the studied topics consists in the investigation of “the mechanical evolution of structures", and especially the analysis of the mechanical response of large underground galleries with concrete liner during the reversibility period (0 - 100 years) using the constitutive law (endoviscoplastic) with the lowest set of parameters. The main objective of this study is to know the impact of the use of this law (and various associated parameters) on the design of structures and to compare with the in situ experiment. The computations of this study allow us to understand the efforts in cementitious components (liner) subjected to claystone loading (with creep) and to analyze the mechanical response of this type of work on the reversibility period. Variability loading of concrete structures is studied using several cases: short-term variation parameters (threshold distortion, dilatancies) and long-term simulation of annular closure (claystone / lining segment) considering interfaces, the packing material, the concrete creep of the liner as well as the delay of applying the liner.