Fatigue Behavior of Granite Subjected to Cyclic Hydraulic Fracturing and Observations on Pressure for Fracture Growth

摘要: This study aims to assess the fatigue behavior of granite subjected cyclic hydraulic fracturing using cylindrical samples. Two sets continuous and injection were carried out monitored with acoustic emission (AE) sensors. In these experiments, life or number cycles failure increased exponentially decreasing maximum pressure during injection. Moreover, although induced more AEs, they lower energy compared those under Similarly, proportion small-to-large-amplitude measured through Gutenberg–Richter b value, was higher in cases cases. implies a probability observing large-amplitude AEs for at pressures. The damage process quantified cumulative absolute AE depicted three-stage process: an initial increase due sample saturation, steady linear before failure, nonlinear rapid leading failure. slope second stage showed relation pre-selected pressure, increasing it associated rate stable enlargement pre-existing microcracks that consequently fractures third stage. Finally, trend required fracture initiation considered be analogous field reopening