Bentonite Saturation from Discrete Fractures - Numerical Model of Non-Uniform Swelling over a Gap
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Date
2017
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
The nuclear disposal concept is based on compacted bentonite barrier placed into a borehole in the host rock. In crystalline rock,
one of the issues is a non-uniform saturation of bentonite caused by inhomogeneity of the rock, typically the flow being
concentrated to fractures. We solve a hydro-mechanical model problem in bentonite in the general engineering multiphysics
simulation software ANSYS. The elasto-plastic transition as result of saturation is represented by a special non-linear stressstrain curve of elastic model (saturation-dependent weakening). The model is further extended to a contact-problem formulation,
where the swelling is possible either as free swelling until filling the gap or as confined state after. It is a synthetic case of one
horizontal fracture crossing a vertical borehole. We demonstrated that for large time period, the saturation is limited to a part of
the volume, producing a non-uniform stress field in the whole volume. The stress is also controlled by the gap width.
Description
Subject(s)
bentonite, coupled process, hydration, modelling, swelling
Citation
ISSN
18777058