3D analysis for predicting the rock mass behavior of a research shaft and gallery considering excavation damaged zone

Seno, Yasuhiro; Mori, Takayuki*; Goke, Mitsuo*; Nakama, Shigeo ; Sato, Toshinori*  

The Excavation Disturbed Zone is defined as the zone host rock around an underground excavation whose characteristics are altered by excavation. This includes the Excavation Damaged Zone, Stress Redistribution Zone and Unsaturated Zone. It is assumed that such zone will become a selective pathway for the migration of groundwater and/or radioactive materials. Therefore, for the design of geological repository where low permeability is required, it is important to establish an accurate method for evaluating and predicting the rock mass behavior due to excavation. This paper describes the results of 3D FEM analysis results using two type continuous models that consider the reduction of stiffness of the Excavation Damaged Zone due to blasting.