Abstract:A calculation formula of thermal-hydro-mechanical (THM) coupling crack initiation rate for brittle rock was derived based on the energy conservation law. The self-designed THM coupling fracture test with conductive adhesive electrical measurement method was applied to measuring the THM coupling crack propagation rate of brittle rock continuously. Research results show that both calculation and test results of crack initiation rate increased with increase of the temperature and the hydraulic pressure. They are almost in good agreement, which can prove validity of the calculation formula of THM coupling crack initiation rate.

Key words: crack initiation rate; thermal-hydro-mechanical coupling test; conductive adhesive electrical method; fracture mechanism; brittle rock