Abstract
It has been very difficult to evaluate with accuracy the behavior of rock mass around tunnel, because rock mass possesses time dependent properties. The time dependent displacement of tunnel consists of two mechanisms that are elastic one due to the progression of tunnel face and another due to the visco-plastic properties of rock mass. In this paper, it is emphasized that these mechanisms may be separated by theoretical approach. The tunnel considered is circular in shape, and is assumed to excavated in constant velocity in the isotropic linear visco-elastic homogeneous media. In addition to these assumptions the idea of equivalent initial stress is introduced. It means that the initial stress varies with time correspond to the velocity of progression of tunnel face. The exact solution of convergence is clearly obtained under these conditions using correspondence theory.
