Architecture and management of a geological repository - Andra

5 – Repository Modules• Fitting of the swelling clay plugAs indicated above, the preferred method is compacting in situ in order to provide immediate contactbetween the ground and the swelling clay core.The clay is produced by mixing pellets of various sizes which improves compacting. Initialpositioning is carried out, for example, by pneumatic means or using an Archimedes screw. Drydensities greater than 1.4 can be achieved by such methods without compacting. A piston cancomplete the compacting process if greater densities are required (see Figure 5.2.27).Figure 5.2.27Procedure for removing the sleeve and simultaneously fitting the swelling clayplug (type C cell)• Fitting the retaining plugThe final stage of closing a cell, the fitting of the concrete plug, can be carried out by pouring behindvertical workform fitted with a vent. It can also be carried out using shotcrete; this second solution iscurrently the subject of a demonstration programme as part of the European ESDRED (EngineeringStudies and Demonstration of Repository Design) project.DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM228/495