A Study of the Behaviors of Circumferential Strain in Creep Tests on Rock

Yoshiaki FUJII	Dr., Research Associate, Faculty of Engineering, Hokkaido University, Kita-ku, Sapporo, 060, Japan
Tamotsu KIYAMA	Chief Researcher, Technical Research Institute, Mitsui Construction Co. Ltd., Komaki, Nagareyama, 270-01, Japan
Mizuho OMORI	Student, North East Surrey College of Technology, Nescot Epson Centre, Long Mead Road Epson Surrey, KT19, 9BH, UK
Yoji ISHIJIMA	Dr., Professor, Faculty of Engineering, Hokkaido University, Kita-ku, Sapporo, 060, Japan

J. fo MMIJ, Vol.113, No.3, p.162-168 (1997)

The behaviors of circumferential strain in creep tests on Inada Granite and Kamisunagawa Sandstone were investigated. The following tests, as well as conventional creep and constant strain rate tests, were carried out:

(1)Reloading tests were conducted by reloading at a constant strain rate in the way of the creep tests.

(2)Unloading tests were conducted by unloading when the peak load appeared in the way of the constant strain rate tests.

It was considered from the test results that (1) the points at which the magnitude of the circumferential strain rate reaches the minimum and the magnitude of the circumferential strain acceleration begins to increase are closely related to the point of maximum load in the constant strain rate tests, and (2) the magnitude of the circumferential strain could indicate the degree of rock damage in creep tests as well as in constant strain rate tests.

KEY WORDS: Rock, Creep, Circumferential Strain, Circumferential Strain Rate, Circumferential Strain Acceleration

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