Experimental study on thermal expansion of granite

By using type of MTS810 electro-hydraulic servo material test system that equipping with MTS652.02 high temperature furnace, thermal expansion experiments to granite samples from one of Shan-dong mines under elevated temperature that varies from 100°C to 800°C was performed. The results show that the granite thermal expansion deformation increases with the increasing temperature, and there is a good increasing exponential relation between temperature and thermal strain. The experimental expressions of thermal expansion coefficient is obtained by the experiments, and the integral formula of thermal strain calculation was presented, and the traditionally calculate formula of thermal strain is just an approximately formula of integral formula in a small temperature range. The incremental elastoplastic constitutive equation considering temperature stress is derived.