The Creep Behavior of Sanjome Andesite under Confining Pressure

The time-dependent mechanical behavior of rock (2nd Report)

Abstract

The compressive creep of Sanjome andesite was examined under the confining pressure from 0 to 400 kg/cm².
The results are as follows:
(1) The creep behavior of the specimen can be divided into two stages. During the first period starting immediately after loading, creep rate is continuously decreasing with time and the logarithmic creeplaw fits for most part of this period. In the successive stage, creep rate is increasing monotonously toward the failure.
(2) The characteristic time, tc, at which creep rate takes its minimum is found tobe related to the lifetime of the specimen, tf, by the following equation, tf=2tc. In other word, the period of the first stage is nearly equal to that of the second.
(3) Comparing at the same elapsed time, creep rate increases with creep stress level under a given confining pressure, and increases with confining pressure under a given stress level.