The influence of water-stress loading sequences on the creep behavior of granite.

Water is believed to be a significant factor affecting the short- and long-term strength of rocks. To further understand the effect of water on the mechanical behavior of rocks, we first performed a series of water absorption tests and uniaxial compression tests (different soak times) to guide a time-dependent creep test. Then, uniaxial creep tests under different water-stress sequence conditions and the traditional creep test were performed. Finally, the effect of water distribution on rock strength and failure patterns is discussed. The obtained results show that the water-stress sequences would result in different mechanical behaviors of rock, i.e., the specimens were more likely to fail under the condition of loading followed by soaking than under the condition of soaking followed by loading and loading after soaking. Furthermore, the strength of the specimen with a nonhomogeneous water distribution is greater than that of the homogeneous specimen if they have the same water content. Because the nonhomogeneous water distribution is dry inside the specimen, the homogeneous water distribution affects the entire specimen, leading to greater softening. According to the obtained results, the sequence of loading and soaking should be considered when predicting the stability of rock mass engineering. [ABSTRACT FROM AUTHOR]