Effects of flaw width on cracking behavior of single-flawed rock specimens

摘要

Cracking behavior of flawed samples has been extensively studied in rocks and rock-like materials using experimental and numerical approaches. However, the existing research mainly focuses on the effects of flaw length l and inclination angle alpha on rock mechanical behavior, a limited attention has been given to understand the role of flaw width b on crack initiation and propagation in relation to mechanical parameters of rocks. In this paper, a two-dimensional particle flow code (PFC2D)-based synthetic rock model, which is calibrated by the laboratory sandstone properties, is used to investigate the effects of flaw width on cracking behavior of single-flawed rock samples under uniaxial compression tests. Numerical simulation results show that the flaw width b has significant effects on the crack geometrical parameters (crack initiation location d and crack initiation angle theta). The values of theta and d significantly decrease with the increase of flaw width when b 1.0 mm and their values tend to be stable with the further increase of flaw widths. It is also found that the mechanical properties (uniaxial compressive strength UCS and deformation modulus E-s) of flawed rock samples are related to the crack geometrical parameters (theta and d) and the effects of flaw width on the values of UCS and E-s of single-flawed rock specimens is significant when b 1.0 mm for lower crack inclination angle (alpha 60 degrees).