Abstract: A coupled model including the combination of pressure solution model and stress corrosion model is proposed to simulate the observed strength recovery of limestone fracture. Thus, the coupled model can consider both pressure solution and stress corrosion in modification of the fracture contact area, which is used to predict the frictional healing of the fracture. The simulation results show that the pressure solution model underestimates frictional healing during short hold times, and with extending the hold times, the simulated results of the pressure solution model obviously increase with the growth of temperature, whereas the results are slightly influenced by the effective confining stress. Generally, the stress corrosion model reflects the growth of fracture contact area caused by compaction. Therefore, the coupled model can simulate the frictional healing well observed from Slide-Hold-Slide (SHS) tests. In conclusion, the stress corrosion model should be considered, when the pressure solution model is employed to simulate the frictional healing, especially under short hold times and at low temperatures when the domain effects are mechanical.

Key words: limestone fracture, frictional healing, fracture contact area, pressure solution, stress corrosion