TY - JOUR
T1 - Physical and mechanical behavior of granite containing pre-existing holes after high temperature treatment
AU - Huang, Yan Hua
AU - Yang, Sheng Qi
AU - Tian, Wen Ling
AU - Zhao, Jian
AU - Ma, Dan
AU - Zhang, Chun Shun
PY - 2017/9/1
Y1 - 2017/9/1
N2 - To understand the high temperature effects on the mechanical and failure behaviors of rock, uniaxial compression tests were carried out on granite specimens containing three pre-existing holes using a rock testing system. Based on the experimental results, the influences of testing temperature on the physical and mechanical parameters of granite were analyzed in detail. An obvious color change of tested granite occurs from gray at room temperature to reddish after 450 °C and to red-brown after 900 °C high temperature treatment. The granite volume increases, mass decreases and density decreases with increasing testing temperature. As the temperature increases, the peak strength first increases and then decreases, while the elastic modulus decreases. However, the peak strain changes slightly before 450 °C, increases dramatically up 450 °C. As the bridge angle increases, the mechanical parameters of granite specimens first decrease and then increase. And then, the crack initiation, propagation and coalescence behavior of granite specimens after high temperature exposure was investigated using an acoustic emission (AE) and photography monitoring technique. The cracking process shows that the propagation of crack from the surface of holes leads to the coalescence between adjacent holes. A large AE count and a stress drop are observed during the crack initiation and propagation. The failure modes can be generally classified into three categories: splitting mode, shear mode and mixed mode and they are closely related to heat treatment temperature and bridge angle. Finally, the mechanism causing the differences in the mechanical parameters observed with increasing temperature was discussed based on the SEM observations.
AB - To understand the high temperature effects on the mechanical and failure behaviors of rock, uniaxial compression tests were carried out on granite specimens containing three pre-existing holes using a rock testing system. Based on the experimental results, the influences of testing temperature on the physical and mechanical parameters of granite were analyzed in detail. An obvious color change of tested granite occurs from gray at room temperature to reddish after 450 °C and to red-brown after 900 °C high temperature treatment. The granite volume increases, mass decreases and density decreases with increasing testing temperature. As the temperature increases, the peak strength first increases and then decreases, while the elastic modulus decreases. However, the peak strain changes slightly before 450 °C, increases dramatically up 450 °C. As the bridge angle increases, the mechanical parameters of granite specimens first decrease and then increase. And then, the crack initiation, propagation and coalescence behavior of granite specimens after high temperature exposure was investigated using an acoustic emission (AE) and photography monitoring technique. The cracking process shows that the propagation of crack from the surface of holes leads to the coalescence between adjacent holes. A large AE count and a stress drop are observed during the crack initiation and propagation. The failure modes can be generally classified into three categories: splitting mode, shear mode and mixed mode and they are closely related to heat treatment temperature and bridge angle. Finally, the mechanism causing the differences in the mechanical parameters observed with increasing temperature was discussed based on the SEM observations.
KW - Crack coalescence
KW - Granite
KW - High temperature
KW - Pre-existing holes
KW - Strength
UR - http://www.scopus.com/inward/record.url?scp=85018349359&partnerID=8YFLogxK
U2 - 10.1016/j.acme.2017.03.007
DO - 10.1016/j.acme.2017.03.007
M3 - Article
AN - SCOPUS:85018349359
SN - 1644-9665
VL - 17
SP - 912
EP - 925
JO - Archives of Civil and Mechanical Engineering
JF - Archives of Civil and Mechanical Engineering
IS - 4
ER -