Construction of the PRACLAY Experimental Gallery at the HADES URF

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The successful realisation of the PRACLAY Gallery in 2007 and the crossing with the Connecting Gallery constitutes an important milestone in the Belgian research programme for the geological disposal of HLW. The same excavation technique was successfully applied for the construction of the Connecting Gallery. The feasibility of constructing the disposal galleries and their crossings can therefore be considered proven. The PRACLAY Gallery was constructed by an open-face tunnelling machine. The concrete wedge block lining was designed to withstand both the pressure exerted by the surrounding clay massif as the thermal stresses that will arise during the Heater Test. The construction of the 45 m long gallery took one month. In general the targeted progress rate of 2 m/day was achieved. Prior to the excavation of the PRACLAY gallery several types of sensors were installed in the surrounding host rock and in the segments of the gallery lining and on the tunnelling shield. The measurements aim to gain as much information as possible concerning the THM behaviour of the clay and its response to the gallery excavation. The current results were in line with previous observations and confirm the anisotropic and highly coupled HM behaviour of the Boom Clay.


Original languageEnglish
Title of host publicationClays in Natural and Engineered Barriers for Radioactive Waste Confinement
Place of PublicationParis, France
Publication statusPublished - Mar 2012
EventClays in Natural and Engineered Barriers for Radioactive Waste Confinement - ANDRA, Nantes, France
Duration: 29 Mar 20101 Apr 2010


ConferenceClays in Natural and Engineered Barriers for Radioactive Waste Confinement


  • geological disposal, Boom Clay, tunnel excavation, heater test, thermo-hydromechanical behaviour, gallery crossing

ID: 113558