Cylindrical Cavity Deformation of Jointed Anisotropic Rock Masses. Empirical Approach

Abstract

Interpretations of cavity expansion tests (pressuremeter, radial jack, etc.) are based (in most occasions) on the analysis of the deformability of a cylindrical cavity in a continuous, isotropic, and homogeneous medium. However, many rock masses show an anisotropic behaviour due to the presence of discontinuity planes of different origins. Cavity expansion tests in these media have been studied here with an empirical approach. Several tests have been simulated in a three-dimensional, anisotropic and discontinuous medium—using 3DEC by Itasca—and their deformation has been analyzed in order to establish the principal factors that control the behaviour of the rock mass in these situations. Based on this analysis, it has been developed a new method for the interpretation of the cavity expansion tests carried out in laminated rock masses, which allows estimating the principal deformation moduli of the rock mass (maximum and minimum). This method can be used for any dip of the discontinuity planes.