Abstract：It is very important to investigate fracture behavior of rock after different temperature effects. The aim of this paper is to investigate the influence of temperature on fracture behavior of sandstone through three-point bending test with pre-crack. The paper indicates that the effects of temperature on sandstone fracture behavior are obvious. And the temperature of 125℃ is a threshold temperature. In the temperature point, the average fracture toughness of sandstone reaches maximum, and the crack propagation mode also change. Namely, the intergranular fracture mechanism and the mix fracture mechanism of intergranular and transgranular dominate before and after the effects of 125℃, respectively. In the domain of 100-150℃, the mechanical behavior of sandstone is unstable. The main reasons maybe that the change of pore structure and mechanical behavior of clay material due to the evaporation of internal adsorbed water and interlayer water. From 125℃ to 600℃, the average fracture toughness of sandstone decrease approximately 50%. Some potential reasons, such as the effects of temperature on the consolidation degree between clay and minerals, thermal cracking on sandstone, and the residual stress due to the different thermal property of mineral particles and clay materials after cooling, have been discussed in the paper.
2010, Vol. 31 
