ABSTRACT
The analysis of circular tunnels excavated in elastoplastic continua under hydrostatic stress fields has been one of the main sources of knowledge and insight as far as ground support principles are concerned. The response of such excavations can be pinpointed in a single curve relating the wall convergence to the internal pressure, which in turn can be related to the distance to the face. This curve is usually known as ground reaction curve. This kind of analysis also permits associating the convergence on the wall to the formation of a plastic aureole around a tunnel of radius R under a hydrostatic field stress of magnitude σ0(Pacher, 1964, Panet, 1993, 1995, Salençon, 1969). This simple analysis is often used as a point of departure in studying the mechanics of deformation around underground excavations (Fairhurst, 1991).
