Modeling of failure phenomena in rocks induced by stress concentration (Phase 2)

Toriihara, Makoto*; Maruyama, Makoto*; Kuwahara, T.*; Suzuki, Kenichiro*

JNC TJ7400 2005-032, 206 Pages, 2003/02

JNC-TJ7400-2005-032.PDF:29.17MB

Elucidation of the physical process leading to brittle failure in crystalline rocks and modeling its mechanism is of fundamental importance in evaluating the mechanical and hydraulic properties of EDZ. In this study, Granitic rock columns and plates with circular opening were subjected to triaxial compression and tension tests and measured elastic wave velocity and resisitivity to analyze nucleation and growth of microcracks. The following conclusions were important to note that: (1)During 90% to 100% stress levels to failure stress, it appear that cracks grew on their size but no cracks were nucleated. (2)It was demonstrated that crack tensor F was closely related the second rank tensor V which was determined by measuring elastic wave velocity on at least six direction. (3)The applicability of numerical analysis model based on the micromechanics was introduced. This could be considered the mechanism of the damage growth (microcrack growth) and the interaction among microcracks. (4)On the experiment of Granitic rock plates with circular opening, the process leading to brittle failure and damage growth of the rock around the opening were observed with AE monitoring and so on. (5)In order to evaluate the variety of permeability with the damage growth, it was showed that permeability tensor in terms of crack tensor gave the permeability change in stress history.

Effects of alkaline and nitrate fluids on hydraulic conductivity of compacted bentonite, 3

Takahashi, Shinichi*; Tajima, Takatoshi*; Toriihara, Makoto*; Mihara, Morihiro

no journal, , 

no abstracts in English