[en] The Trou Loulou is an old underground soft carbonate quarry located in Eastern
Belgium. This shallow depth room-and-pillar quarry was mined out from the 16th century for
building stone. Now, it is considered as a cultural heritage. In the same area, an open-pit quarry is
currently mining carbonated rocks for cement production. The Trou Loulou is located in the extension
of this open-pit quarry. Therefore, a stability study was required for determining the security
distance between both sites in order to preserve this heritage when the open-pit comes closer to it.
In this paper, we first describe the geological context. A conceptual model is derived from 2D and
3D surveying of the site. In situ and laboratory mechanical characterizations are performed and
a stability analysis is proposed using 2D finite element modelling. Progressive simulation of the
open-pit quarry shows the occurrence of localized roof failure.
