Rock mechanics studies for ornamental stone quarrying by experimental measurement and numerical modeling

The stability condition of underground excavations have to be assessed to guarantee safe operations within the quarrying working areas. This objective requires a reliable study of the rock mass natural state of stress and of the stress redistribution induced by the excavations. This goal is often complicated by difficult geological conditions induced by tectonic stresses, complex topographies and large and irregular excavation geometries. Consequently, the acting state of stress need to be measured by specifical in situ measurement devices. This work refers on an in situ measurements campaign carried out by hydraulic fracturing techniques in a marble quarry in the Carrara marble basin. The difficult path carried on for interpretation of the measurements is described in this paper. In particular, numerical modelling performed by Boundary Element Method (BEM) to study the influence of the surface topography and of the excavation geometry and by Distinct Element Method (DEM) in order to evaluate the influence of rock discontinuities in the measurement zone is illustrated in this work. Parametrical analysis of the rock mass mechanical features is described in order to calibrate the numerical models and to interpreter the experimental results