Stress–Strain Investigation of the Rock Mass Based on Overcoring with CSIRO HI Cell Test and Numerical Modeling: A Case Study from an Italian Underground Marble Quarry

Abstract

The present research illustrates the application of a methodological approach to studying the stress–strain distribution in a marble quarry of the Apuan Alps mining area (Italy). This study has been carried out in the framework of a project involving the University of Siena and the UOC Ingegneria Mineraria—USL Toscana Nord-Ovest, Tuscany Region. This stress–strain analysis aims foremost to monitor the slope stability conditions to guarantee a safe workplace for the personnel involved in mining activities, and to enable more sustainable long-term planning for excavation and production. The involved survey activities are as follows: (i) terrestrial laser scanning; (ii) engineering–geological data mapping; and (iii) in situ marble stress measuring through four CSIRO-type cell tests executed in different locations and at various depths within the underground excavation walls. The gathered data converged into numerical models of the quarry, both in 2D (DEM) and 3D (FEM), calibrated by in situ stress results through a rigorous back analysis assessment using least squares procedures. The created models represent a valuable tool for the identification and securing of risk areas and for future excavation planning in respect of the site efficiency and safety.

Applying SLAM-Based LiDAR and UAS Technologies to Evaluate the Rock Slope Stability of the Grotta Paglicci Paleolithic Site (Italy)

“…The high stress values shown in the AA' cross-section, especially at the entrance of the cave (i.e., 39 MPa in Figure 17), can probably be explained by the fact that the left lateral wall of the Atrium dome has a thickness that is insufficient to distribute the stresses developed by the roof material's weight. This hypothesis could be confirmed by calibrating the model stresses through the execution of in situ measurements, as described in [82].…”

“…Numerical analysis has allowed for the identification of areas where critical issues or failures may occur and could lead to episodes of instability. To critically assess the obtained differential stress values, the method described in [82] can be used; it allows the calculation of the threshold value of the differential stress responsible for the creation of new failures in a slightly fractured rock mass.…”