A three-dimensional numerical modelling of an underground gallery excavation considering the influence of sedimentary rock cross-anisotropy
A three-dimensional numerical modelling of an underground gallery excavation considering the influence of sedimentary rock cross-anisotropy
ABSTRACT: Clayey geomaterials are favourable underground media for radioactive waste disposal. In sedimentary geomateri-als, an anisotropic behaviour depending on the loading direction is frequently observed. This paper investigates the effect of the inherent structural anisotropy of the Callovo-Oxfordian (COx) claystone on the construction of a single circular gallery at great depth. The rock matrix behaviour is assumed to follow a classical Drucker-Prager elastoplastic constitutive law with shear strength hardening in which anisotropy is implemented using the fabric tensor approach. The study focuses on a three-dimen-sional mechanical modelling of the short-term response of the clay rock, the shape and extent of the excavation damaged zone (EDZ) around the gallery using a plastic indicator and the convergence of the gallery walls. The model implementation is realised with the finite element analysis solver Code Aster. Simulations are performed for different in-situ stress states and comparisons are made based on the field observations. The results highlight the influence of anisotropy in the short-term extension of the plastic zone and trigger future prospects for complex numerical models.
Panteleimon Rapanakis; Benoit Pardoen; Denis Branque; Jan Cornet; Gilles Armand
10th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE2023)
10. Tunnelling and mining applications
https://doi.org/10.53243/NUMGE2023-78
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