Analyzing slope stability in bimrocks by means of a stochastic approach

Bimrocks (block-in-matrix rocks) are chaotic geological formations defined as heterogeneous mixtures of hard rock blocks encased in a fine-graded matrix. The inherent geometric, lithological and mechanical variability of bimrocks imply a great challenge in their characterization and modeling. A common practice when planning engineering works in these complex formations is to neglect the contribution of blocks and assign the strength and deformation properties of the weaker matrix to the whole rock mass. However, this assumption can lead to erroneous results and, consequently, to technical problems during construction works. The aim of this study was to investigate stability of theoretical slopes in bimrocks using a stochastic approach, in order to consider the spatial and dimensional variability of rock inclusions. Many 2D stability analyses were performed on slope models with simple geometries, elliptical block shapes and variable block contents. The results were compared to those obtained in a previous work, where slope stability analyses were carried out on bimrocks with blocks of circular shape. The findings of this research confirm that rock inclusions play an important role and strongly influence the slope stability of bimrocks. Furthermore, the advantages of using a stochastic approach when working with these heterogeneous materials are highlighted.