Experimental program during the construction of an underground laboratory in a plastic clay layer at 215 m depth¹1

The construction of a shaft and a experimental gallery has started under the site of the Centre d'Etude de l'Energie Nucléaire (C.E.N./S.C.K.) at Mol in Belgium.The shaft, excavated by means of freezing technique, will be 225 m deep and will give access to an horizontal gallery 30 meters long with circular cross section, excavated in plastic clay at a depth of -220 m.The C.E.N./S.C.K. will take advantage of the shaft sinking to implant a series of measuring devices in the clay in order to assess certain geomechanical parameters of the in situ clay as well of the resistance characteristics of the shaft lining. This geotechnical campaign will allow to get experience about frozen clay at that depth and to test the measuring devices prior undertaking a long term extensive experimental campaign in the gallery.