Experimental study on post-peak stick-slip failure of three different rock joints under direct shear tests

Abstract

For discovering the post-peak stick-slip failure characteristics of joint in rock mass and mechanism of the post-peak shear failure, a coupling 3D scanning and 3D engraving method are presented to create three kinds of rock joints (sandstone, marble, and granite) with identical morphology, and corresponding direct shear tests and synchronous Acoustic emission monitoring are conducted. A multi-aspect analysis is performed to recognize the mechanical behavior of post-peak stick-slip and its meso-fracture mechanism of rock joint. The results indicate that the occurrence of post-peak stick-slip failure of rock joint mainly depends on rock types, and its failure type changes with the increase in the normal stress. The post-peak stick-slip phase has the same failure type and dominant frequency range as those of the shear load peak phase. Thus, the post-peak stick-slip failure can be understood as a small shear peak failure. The failure type of the shear load peak can be used to predict post-peak stick-slip failure of rock joint. It has important reference significance for precursor identification of shear disaster in engineering rock mass.