ABSTRACT:

In order to examine the effect of the stress corrosion, the uniaxial compression tests in a chamber are conducted on Kumamoto andesite, changing the surrounding non-atmospheric environment of rock. From the experimental results, it is concluded that not only strength but also hysteresis of rock change, depending on the environment, and that the water is the most effective agent that promotes the stress corrosion among the materials used in this research.

INTRODUCTION

The strength of rocks is affected by the density, the shape and the direction of cracks, the strain and stress rate of loading, the stress state, the temperature and the existence of water in vapor phase or in liquid phase, and so on. Furthermore, it is well known the fact that the strength of same kind rock under uniaxial compression test performed in summer is smaller than that in winter. This mean that the strength of rock is influenced on the condition of air on the season of the year, namely moisture. Many researchers have indicated that the strength of rocks is dependent on the subcritical crack growth due to stress corrosion caused by water. The stress corrosion crack growth occurs because the chemical action of an environmental agent, such as water, weakens the strained bonded at crack tips and facilitates crack propagation, and the crack velocity as a stress intensity factor is exceeded the stress corrosion limit increases with increasing water vapor pressure (Atkinson et al. 1987). Charles (1959), Krokosky et al. (1968) and Mizutani et al. (1977) have shown the experimental results that the strength of rocks under uniaxial compression test increases with decreasing water vapor pressure in atmosphere. However, a few researchers confirmed that the agent of stress corrosion is water or water vapor.

This content is only available via PDF.
You can access this article if you purchase or spend a download.