The Effects of Structure on the One Dimensional Compression Behaviour of a Porous Calcarenite

Human settlements built on weak rock deposits are often characterized by instabilities or collapse that may involve the underground cavities and consequently the above buildings. Underground calcarenite quarries in Marsala have been involved in a number of collapses that have seriously damaged numerous buildings. Unfortunately proper engineering solutions have not yet been identified according to the different and special cases and to the properties of this structured material. In order to investigate structure effects on the behaviour of the porous calcarenite of Marsala, this paper presents a comparison between the one dimensional compression behaviour of the intact rock and of the same weak rock in the reconstituted state. The investigated lithotype is a metastable rock whose mechanical behaviour is strongly affected by its structure, which is commonly distinguished in the literature as a combination of fabric and bonding. The investigation has highlighted original results, not reported in the literature for this material, such as the irrelevance of bonding in determining the stiffness. A laboratory study was also undertaken to assess the use of polymer treatment or inorganic consolidants as a solution to improve the mechanical behaviour of this weak rock.