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A THERMO-MECHANICAL BEHAVIOUR OF BOOM CLAY.

Objective

THE UNDERSTANDING OF THERMAL EFFECTS DUE TO DECAY HEAT LIKE PORE PRESSURE RISE, CHANGE IN MECHANICAL PROPERTIES AND IN THE HYDRAULIC FIELD UNDER HIGH LITHOSTATIC PRESSURES IS FUNDAMENTAL IN THE EVALUATION OF SAFETY AND IN THE DESIGN OF NUCLEAR WASTE REPOSITORIES IN CLAY.
FOR THIS PURPOSE A THERMO-HYDRO-MECHANICAL MODEL HAS BEEN DEVELOPED IN ISMES. ITS SUITABILITY IN REPRODUCING THE THERMO-MECHANICAL RESPONSE OF THE SAMPLES TESTED UNDER DIFFERENT LOADING CONDITIONS HAS BEEN TRIAXIAL CELL OPERATING IN ISMES LABORATORIES ON VARIOUS TYPES OF STIFF CLAYS, EITHER REMOULDED AND UNDISTURBED.
FURTHERMORE, THE INTERPRETATION PROCEDURES OF THERMAL TESTS SHOWED THAT FOR SOME OF THE CLAY TESTED THE CAMPANELLA AND MITCHELL PROCEDURE CAN LEAD TO INCONSISTENT RESULTS.
IN ORDER TO STUDY POSSIBLE REASONS FOR THIS INCONSISTENCY, FIRST THERMAL EXPANSION COEFFICIENT VALUES WILL BE STUDIED REFFERRING TO THE CONDITIONS OF WATER IN STIFF CLAYS, WHICH ARE SUSPECTED TO AFFECT SIGNIFICANTLY ITS THERMAL BEHAVIOUR. THIS STUDY WILL BE CONDUCTED WITH AECL OF CANADA.
THE RESULTS OF THIS RESEARCH COULD AFFECT ALSO THE PREDICTED UNDRAINED RESPONSE OF CLAY IN TERMS OF PORE PRESSURE RISE.
IN THE MEANTIME A BETTER UNDERSTANDING OF THERMO-MECHANICAL BOOM CLAY BEHAVIOUR IS FORESEEN IN ORDER TO IMPROVE THE MODEL.
THERMO-MECHANICAL EFFECTS ON CLAY DUE TO REALISTIC DISPOSAL GEOMETRIES WILL BE THEN STUDIED WITH THIS MODEL WITH THE COOPERATION OF SCK/CEN.
SIMILAR STUDIES ARE PLANNED ALSO FOR SAND/BETONITE MIXTURES, WIDELY ADOPTED FOR BACKFILLING.

1. MICROSTRUCTURAL STUDIES
2. SAMPLING OF THE BOOM CLAY IN THE MOL SITE.
3. EXPERIMENTAL TESTS IN THE HITEP APPARATUS ON NATURAL CLAYEY AND ARTIFICIAL SOILS.
4. IDENTIFICATION OF MATERIAL PARAMETERS ON THE BASIS OF EXPERIMENTS ON BOOM CLAY
5. INTRODUCTION OF THE OPTIONS EXPECTED FROM ACTIVITY 1 IN THE MATHEMATICAL MODEL.
6. CHECK ON THE RSSULTS OF THE LABORATORY TESTS USING THE ABOVE MODEL.
7. DEFINITION OF THE BOUNDARY VALUE PROBLEMS TO BE TREATED ON THE BASIS OF PROSPECTIVE IN-SITU EXPERIMENTS AND/OR TYPICAL DISPOSAL TECHNOLOGY AT MOL SITE.
8. SIMULATION OF CLAY MASS BEHAVIOUR WITH REFERENCE TO THE PROBLEMS ENVISAGED IN ACTIVITY 7
9. EVALUATION OF SIMULATION RESULTS

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

ENEL.HYDRO SPA
Address
Via Pastrengo 9
24068 Seriate
Italy

Participants (2)

ATOMIC ENERGY OF CANADA LTD
Canada
Address

Manitoba
CEN-SCK
Belgium
Address

Mol