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DIMENSIONING OF LINING OF GALLERIES EXCAVATED IN DEEP CLAY FORMATIONS.

Objective

THE DIMENSIONING OF LINING OF GALLERIES IN DEEP CLAY FORMATIONS DEPENDS DIRECTLY ON THE LONG TERM STRESS UNDERGONE BY THE SUPPORT.
THE MECHANICAL CHARACTERISTICS OF THE CLAY FORMATION COULD BE USED TO OPTIMIZE THE LINING. IT SEEMS POSSIBLE TO MINIMIZE THE PRESSURE IN THE SUPPORT, BY ALLOWING THE EXCAVATION WALL TO CONVERGE ENOUGH WITH TIME. DIFFERENT FACTORS CAN BE CONSIDERED TO REACH THIS OBJECTIVE, AS THE TIME LAG FOR THE ROCK TO COME TO CONTACT WITH SUPPORT OR THE FLEXIBILITY OF THE LINING.

THE OBJECTIVE OF THIS WORK IS TO IMPLEMENT A LINING WICH ANSWERS THIS CRITERIUM. IT IS MADE OF STEEL RIBS SHOWING A SIGNIFICANT IFFNESS WITH SLIDING DEVICES ADAPTED AT THE JOINT ELEMENTS, ALLOWING THE CONVERGENCE. THIS CONFIGURATION WILL TEST THE CLOSURE - CONFINEMENT CONCEPT : THE CONVERGENCE OF THE WALL PREVENTS THE CONFINEMENT TO RISE ABOVE A CERTAIN THRESHOLD. MOREOVER THIS LINING PRESENTS PRACTICAL ADVANTAGES I.E. THE HANDINESS AND EASE OF TRANSPORT, THE RAPIDITY FOR BUILDING AND THE SMALL VOLUME OF MATERIAL TO DIG AND DISPOSE.

THE CONCEPTION OF THE PROJECT AND THE STUDY OF THE MASSIF-LINING BEHAVIOUR ARE CONDUCTED BY LMS (LABORATOIRE DE MECANIQUE DES SOLIDES DE L'ECOLE POLYTECHNIQUE). ENGINEERING DEPARTMENT OF SIMECSOL WAS RESPONSIBLE FOR THE INSTRUMENTATION AND MEASUREMENTS DURING CONSTRUCTION, COLLABORATION OF CSN/SCK FOR SURVEYING WAS SINCE REQUESTED.

1. BUILD UP OF A 12.5 M LONG TEST GALLERY IN THE CONTINUATION OF A CONCRETE DRIFT MADE BY THE CEN/SCK. A TRANSITION ZONE OF 2 M WITH CONCRETE ARCHSTONES PREVENT ANY PERTURBATION OF THE CEN GALLERY.
2. MEASUREMENT OF :
- CLOSURE OF IMPLEMENTED RINGS.
- SLIDING OF THE RIBS,
- RIB STRAIN
- PRESSURE ON THE OUTER FACE LINING,
- DISPLACEMENT INSIDE THE CLAY FORMATION,
DURING AND AFTER EXCAVATION, FOR 24 MONTHS AT LEAST.
3. INTERPRETATION OF RESULTS.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

NATIONAL RADIOACTIVE WASTE MANAGEMENT AGENCY OF FRANCE
Address
Rue Jean Monnet 1-7
92298 Chatenay Malabry
France