Influence of Different Support Systems on Drifts Closure Evolution in Callovo-Oxfordian Claystone
Résumé
At the Meuse/Haute-Marne Underground Research Laboratory several research programs have been dedicated to: (1) knowledge improvement of the Callovo-Oxfordian claystone response to the excavation; (2) development of the different disposal systems. In order to increase the understanding of the rock mass formation and support interaction, a drift composed of different support systems has been monitored for several years. As this one is oriented along the minor horizontal principal stress, the measurements exhibit an anisotropic closure of the cross section with the vertical convergence being higher than the horizontal one. It is thus of interest to evaluate the effect of flexible support composed of compressible wedges and of the final concrete lining on the closure evolution. Also, extensometers measurements and the stresses on the temporary support are analyzed in different zones of the drift. Finally, the results are compared to those obtained from other drifts excavated in similar conditions.