Three groups of experiments on brittle-plastic transition and instability modes of granite were performed in a triaxial vessel with solid pressure medium at high temperature and high pressure. The results of experimen...Three groups of experiments on brittle-plastic transition and instability modes of granite were performed in a triaxial vessel with solid pressure medium at high temperature and high pressure. The results of experiments show that brittle faulting is the major failure mode at temperature <300℃, but crystal-plastic deformation is dominate at temperature >800℃, and there is a transition with increasing temperature from semi-brittle faulting to cataclastic flow and semi-brittle flow at temperatures of 300～800℃. So, temperature is the most influential factor in brittle-plastic transition of granite and confining pressure is the second factor. The results also show that progressive failure of granite occurs at lower pressure or high temperature where there is crystal plasticity, and sudden instability occurs at room temperature and high pressure (>300MPa) or high temperature and great pressure(550℃600MPa ～650℃700MPa), and a broad regime of quasi-sudden instability exists between the T-P condition of progressive failure and sudden instability. So, instability modes of granite depend simultaneously on the pressure and temperature.展开更多
Deformation experiments of Carrara marble were conducted under increasing temperatures (temperatures 300℃ - 550℃, confining pressure 0. 5Mpa, strain - rate 5 × 10- 6 s-1 ). The experiments reveal that calcite r...Deformation experiments of Carrara marble were conducted under increasing temperatures (temperatures 300℃ - 550℃, confining pressure 0. 5Mpa, strain - rate 5 × 10- 6 s-1 ). The experiments reveal that calcite rocks show different deformation behaviors and corresponding microstructural characteristics under different temperatures. By analyzing microstructural characteristics, preferred grain shape orientation variation of the primary rocks and deformed specimen, the deformation features of Carrara marble are summarized: twinning, fracturing dominates deformation of the rocks at temperatures between 300℃ and 450℃; dynamic recrystallization occurs in the temperature range of 450- 550℃; the brittle to crystalline plasticity transition deformation is observed at around 450℃, twinning and crystal - plastic deformation become dominant with further increasing temperature.展开更多
文摘Three groups of experiments on brittle-plastic transition and instability modes of granite were performed in a triaxial vessel with solid pressure medium at high temperature and high pressure. The results of experiments show that brittle faulting is the major failure mode at temperature <300℃, but crystal-plastic deformation is dominate at temperature >800℃, and there is a transition with increasing temperature from semi-brittle faulting to cataclastic flow and semi-brittle flow at temperatures of 300～800℃. So, temperature is the most influential factor in brittle-plastic transition of granite and confining pressure is the second factor. The results also show that progressive failure of granite occurs at lower pressure or high temperature where there is crystal plasticity, and sudden instability occurs at room temperature and high pressure (>300MPa) or high temperature and great pressure(550℃600MPa ～650℃700MPa), and a broad regime of quasi-sudden instability exists between the T-P condition of progressive failure and sudden instability. So, instability modes of granite depend simultaneously on the pressure and temperature.
基金National Natural Science Foundation of China(49872071)
文摘Deformation experiments of Carrara marble were conducted under increasing temperatures (temperatures 300℃ - 550℃, confining pressure 0. 5Mpa, strain - rate 5 × 10- 6 s-1 ). The experiments reveal that calcite rocks show different deformation behaviors and corresponding microstructural characteristics under different temperatures. By analyzing microstructural characteristics, preferred grain shape orientation variation of the primary rocks and deformed specimen, the deformation features of Carrara marble are summarized: twinning, fracturing dominates deformation of the rocks at temperatures between 300℃ and 450℃; dynamic recrystallization occurs in the temperature range of 450- 550℃; the brittle to crystalline plasticity transition deformation is observed at around 450℃, twinning and crystal - plastic deformation become dominant with further increasing temperature.
