Significant Parameters in Elastoplastic Analysis of Underground Openings

Abstract

In this paper the authors show how it is possible to reduce the number of significant parameters appearing in typical rock mechanics boundary value problems of rock engineering and tunneling. Further, they present methods to gain information concerning the solutions to these problems, presuming the rock mass obeys the well-known, and in geomechanics widely used, Mohr-Coulomb yield criterion. The system of differential equations that governs boundary value problems with a Mohr-Coulomb elastoplastic material can be reformulated by means of simple substitutions in such a way that cohesion and Young's modulus do not explicitly appear. This makes substantial savings of computational effort possible, and contributes to a better understanding of the structure of the solution. Computational results obtained for some values of Young's modulus, cohesion, initial stresses, and boundary tractions can easily be transformed to the results for other values. The transformed equations suggest very clearly the influence of cohesion, i.e., as compared to the effect of a support pressure.