大理石におけるサブクリティカルき裂進展の周辺環境依存性

Abstract

It is important to investigate time-dependent deformation and fracturing in rock for the purpose of ensuring the long-term stability of structures in a rock mass. Subcritical crack growth is one of the main causes of time-dependent fracturing in rock. It is known that subcritical crack growth is influenced by not only stress but also surrounding environment. Studies of subcritical crack growth have been widely conducted for silicate rocks such as igneous rocks and sandstones. On the other hand, information of subcritical crack growth in carbonate rocks is not enough. Especially, influence of surrounding environmental conditions on subcritical crack growth in carbonate rocks has not been clarified yet. In this study, we investigated subcritical crack growth in carbonate rocks. Specifically, we investigated the influence of temperature and relative humidity on subcritical crack growth in air and in water. Macedonian marble was used as a rock sample. To measure subcritical crack growth, we used the load relaxation method of the double-torsion test. It was shown that the crack velocity increased when the temperature was higher at a constant relative humidity in air and in water. In addition, the crack velocity increased with increasing the relative humidity at a constant temperature. It is concluded that the temperature and relative humidity influence subcritical crack growth in carbonate rock in air and in water. From the results obtained in this study, it can be suggested that the condition with low temperature and low humidity is desirable for the long-term integrity of a carbonate rock.