ABSTRACT
Authors studied a Parisian underground metro station located in a complex geomorphological/geological site, characterized by the presence of in-place and displaced rock masses both simultaneously in contact with the structures. The displaced masse consists of metric to decametric blocks of limestone surrounded by a metric-thick matrix of scree. A robust method is used first to identify the boundary between in-place and displaced masses. The mechanical properties of the displaced masses are then estimated. The size of the blocks compared to the dimensions of the structures makes it challenging to characterize the rock mass as a homogeneous material. On the other hand, identification and modeling of every individual block and surrounding screes was not possible. This article presents different methods used to determine “equivalent” parameters for the displaced rock masses. The article presents also the challenges encountered in sampling and characterizing sensitive chalk resulting in the use of very high-pressure pressuremeter test.
