Studies about strength recovery and generalized relaxation behavior of rock (Contract research)

Hiramoto, Masayuki; Kobayashi, Yasushi; Okubo, Seisuke*

Strength recovery and generalized relaxation behavior of rock were examined. The sample rock was Wakkanai-formation shale. In Chapter 2, strength recovery characteristic of rocks was examined. It was found that strength recovery increases with increase of testing time or load-holding time. It was interesting that the sample with relatively small unconfined compressive strength showed higher strength recovery. These results were obtained for only two sample rocks. Therefore, the accumulation of the data is needed in future to evaluate the influence of the boring places quantitatively. In Chapter 3, the generalized relaxation behavior of rock was examined. As a result, scatter in obtained data is considerably large, so the accumulation of the data is needed in future to understand rightly the complicated generalized relaxation behavior.