Study on the Effects of Joint Inclination and Size Effect on the Failure Process of Rock-like Materials

Abstract

To explore the effects of joint inclination angle and the size on the mechanical properties and failure process of rock-like specimens, a series of uniaxial compression tests were carried out on rock-like specimens.The specimens are consist of two sizes and contain three parallel joints with various inclination angles. During testing, the variation characteristics of apparent strain field of specimens is recorded by digital image correlation (DIC) system. Testing results reveal the uniaxial compression strength of the specimen decreases gradually with the joint inclination increases from 0° to 60°, while increasing gradually with the joint inclination increases from 60° to 90°. In addition, the peak compression strength of the large-size specimens is obviously lower than that of the small-size specimen when the joint inclination angle is 0°~30°. By contrast, the peak compression strength of the large-size specimens is the same as that of the small-size specimen when the angle is 30°~60°, approximately. But, the peak compression strength of large-size specimen is obviously higher than that of small-size specimen when the joint inclination angle is between 60° and 90°. Finally, five different types of cracks are observed in this work, i.e., tensile crack,airfoil tension crack,pull-shear mixing crack,secondary crack and far field tensile crack.