Study on crystalline rock for evaluating method of long-term behavior; FY2012 (Contract research)

Fukui, Katsunori*; Hashiba, Kimihiro*; Tanno, Takeo; Hikima, Ryoichi; Sanada, Hiroyuki; Sato, Toshinori  

It is very important to understand the time-dependent behavior of rock for evaluating long-term mechanical stability. The purpose of this study is determining the mechanisms of time-dependent behavior of rock by the precise test, observation and measurement, to develop methods for evaluating long-term mechanical stability. This report describes the results of the activities in fiscal year 2012. In Chapter 1, we provide an overview and the background to this study. In Chapter 2, the results of a long-term creep test on Tage tuff, started in fiscal year 1997 are described. In Chapter 3, the experimental results concerning the loading-rate dependency of strength were examined to understand the time-dependency of rock. In Chapter 4, the stability of tunnels, around which rock stress is larger than that around a circular tunnel, were examined to obtain useful information on the future plan for tests in the underground research laboratory.