Micromechanics-based continuum model for a jointed rock mass and excavation analysis of Shiobara powerhouse

Abstract

Mechanical behaviors of rock mass with discontinuities are of great concern. To find solutions to engineering problems such as a design of a large-scale cavern in jointed rock mass, a well-defined mathematical model must be settled. The number of joint involved in the rock mass is, however, so enormous that it is almost impossible to treat them individually. Hence, the jointed rock mass is replaced with an equivalent continuum. The point is how to ensure the equivalence between the two problems. “Micromechanics-Based Continuum (MBC) Modeling” provides a constitutive equation in the equivalent continuum problem with using an average operation of strain and stress over a representative volume element (R.V.E). In this article, the joints involved in the rock mass are regarded as microstructure and the MBC approach for the jointed rock mass is resented. To examine the performance of the proposed method, the excavation of the Shiobara powerhouse constructed by the Tokyo Electric Power Co., Ltd. is analyzed and it is demonstrated how successfully the MBC approach answers the engineering problems.