Investigation of the long-term strength of Jinping marble rocks with experimental and numerical approaches

This work describes investigation of the long-term strength of marble rocks in a stability assessment of deeply buried Jinping headrace tunnels. First, a series of long-term axial compression tests were conducted, with which the fitted long-term strength curve for marble rocks was determined. Then, Potyondy’s parallel-bonded stress corrosion (PSC) model was used to perform a numerical static fatigue test. The PSC parameters of the marble rocks were back-analyzed based upon the long-term loading tests. Finally, a small-scale Particle Flow Code (PFC)-based model was constructed for a headrace tunnel, and the long-term stability of the modeled tunnel was assessed.