ABSTRACT
This chapter proposes a back analysis method for determining displacement distributions around the underground openings excavated in jointed rock masses. The deformational behaviour of jointed rock masses may be classified into the following three modes namely: spalling of joints, sliding along a particular slip surface, and plastic flow. Consequently, the mechanical model used in the back analyses must represent all these deformational modes. In the proposed back analysis methods, a simple linear mechanical model is introduced, in which the three different deformational modes can be analysed by using a single model based on continuum mechanics. In the back analyses, the normalised initial stress is also back-calculated from the measured displacements, which are used together with the back-calculated anisotropy parameters as input data for the ordinary finite element analyses, resulting in the displacements around the cavern being calculated.
