GEOLOGICAL ISOLATION OF RADIOACTIVE WASTE IN CLAY FORMATIONS - FRACTURING AND FAULTING AS A POSSIBLE FAILURE MODE OF THE GEOLOGICAL BARRIER
Clay formations can fracture, in spite of their plastic behaviour. These discontinuities can be gathered into two classes: 1) faults, generally caused by tectonic movements, due to causes external to the clay formation. (The response of argillaceous materials can be quite variable). 2) fissures of variable dimensions, probably due to causes internal to the clay formation. (The mechanisms responsible for the fissures are not clear). In general, when the clay possesses a sufficient degree of plasticity, the former type of discontinuity is watertight, but fractures due to desiccation and decompression can be permeable. On the basis of data collected and illustrated in the present paper, it seems reasonable to suppose that water migration by secondary permeability through a significant thickness of plastic clay at depth is unlikely; but at present there are more questions than answers. The entire problem appears rather uncertain; at present it seems difficult unambiguously to define a set of parameters governing the secondary permeability in clays. A number of studies are suggested towards the improvement of the general understanding of the phenomena.
Bibliographic Reference: EUROPEAN APPLIED RESEARCH REPORTS - NUCLEAR SCIENCE AND TECHNOLOGY SECTION, VOL. 6 (1985), NO. 4, PP. 969-1001, (EUR 9729 EN).
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Record Number: 1989124009000 / Last updated on: 1987-01-01
Available languages: en