3D geological modeling for slope stability problems; the case study of the Corno Zuccone sackung, Val Taleggio (Italy)

A 3D geological reconstruction of the Corno Zuccone sackung, Val Taleggio, Bergamo, was carried out by means of GOCAD, a special software for 3D applications. The sackung occurs in the sedimentary cover of the Southern Alps, within a klippe of Dolomia Principale (DP) thrusted upon the plastic shale of the Argillite di Riva di Solto Fm. (ARS). The klippe is bounded by strike-slip faults which constrain the subsequent gravitational movements. Topographic (contour lines) and geological data (geological, structural, and geomorphological linear elements, cross-sections, faults and beds attitude), previously stored in a GIS, have been translated and imported into GOCAD for the construction of the 3D model. 3D modeling has allowed the internal consistency of the input data to be checked, thus improving the geometrical and kinematic interpretation of the sackung. A 2D geomechanical model has been built through a discrete elements code, in order to analyse the mechanism of formation of the sackung, based on the obtained 3D reconstruction. 2D and 3D models both suggest the occurrence of a basal sliding surface located within the ARS causing a horizontal shift of about 150 m of the slided rock mass.