Influence of Water on Subcritical Crack Growth in Marble

Long-term stability is required for the structures in a rock mass. For this purpose, a better understanding of time-dependent crack propagation in rock is required. Subcritical crack growth is one of the main mechanisms responsible for the time-dependent behaviour of rock. Subcritical crack growth in silicate rock has been studied well. On the other hand, however, information about subcritical crack growth in carbonate rock is not enough. In this study, subcritical crack growth in marble was investigated. Especially, we investigated the influence of water on the relationship between the crack velocity and the stress intensity factor for marble. It was shown that the crack velocity in water is much higher than that in air. The difference between the crack velocity in water and that in air for marble was larger than that for igneous rocks. It was also shown that the value of subcritical crack growth index in water was lower than that in air. This tendency agrees with that for igneous rock. It is concluded that the weakening of marble is enhanced by water.