• Research paper •

### Meso-failure of sandstone under temperature effects and DSCM study on deformation field

Zuo Jianping Heping Xie Huaiwen Wang Yuan Fang

• Received:2007-06-18 Revised:2008-06-30 Online:2008-11-25 Published:2008-11-25

Abstract: The meso-failure progress of sandstone under temperature effects was observed and studied in-situ through Scanning Electron Microscopy (SEM). The SEM observations under thermal-mechanical coupling effects showed the brittle fracture on the different places, independent bearing minerals and the bifurcated cracks in the sandstone sample. The numer of microcracks or the branch cracks near the main crack was large below the temperature of 100°C and small over 150°C. Within the temperature from 25°C to 300°C, the fracture toughness of sandstone increased firstly and then decreased. There was the threshold temperature of 150°C for sandstone at meso-scale. With the rising temperature, the failutre of sandstone will obtain the transition from brittle to ductile behavior. Sandstone failure modes were experimental observed, such as transgranular, intergranular and mixed mode. Meanwhile, the deformation field of sandstone was measured using digital speckle correlation method (DSCM).