为了研究不同加热速率处理后花岗岩的断裂特性与损伤机理,对中心直裂纹巴西圆盘(CSTBD)试样在4组加热温度下分别进行4种加热速率的高温处理,冷却至室温后使用电液伺服压力机进行巴西劈裂实验,分析其静力学断裂过程。结果表明:(1)经过不同高温处理的花岗岩,从脆性破坏向延性破坏转变。(2)在同一目标温度下,经不同加热速率处理的花岗岩,峰值破坏载荷随着加热速率的增大而降低。表观颜色无明显区别,而表观裂缝逐渐增多。(3)不同加热速率下,200℃和400℃下的纵波波速和弹性模量变化较小,而600℃以上时,随着加热速率的增大,纵波波速和弹性模量显著降低。(4)花岗岩的断裂韧度随着温度升高呈现逐渐衰减特征,同一温度下花岗岩试样的I型断裂韧度值随加热速率的增大而减小,400℃下加热速率对花岗岩断裂韧度的影响最大。

This study investigates the fracture characteristics and damage mechanism of granite after treatment under different heating rates. The cracked straight-through Brazilian disc(CSTBD) specimen was used for high-temperature treatment with four heating rates under four sets of heating tempera- tures. The Brazilian splitting experiments were carried out using electro-hydraulic servo press after cool- ing down to room temperature,and the static fracture process was analyzed to investigate the effect of heating rate on the fracture mechanical properties of specimens. The results show that:(1) Granite trea- ted at different high temperatures shifted from brittle to ductile damage. (2) The peak damage load of granite treated with different heating rates at the same temperature decreased with the increase of heat- ing rate. At the same temperature,the increase of heating rate doesn’t lead to obvious difference in the apparent color of granite,but with gradual increase of apparent cracks. (3)At different heating rates,the OF MINING SCIENCE AND TECHNOLOGY longitudinal wave velocity and elastic modulus at ℃ and ℃ show subtle changes,yet at ℃ and above,the longitudinal wave velocity and elastic modulus decrease significantly with the increase of heating rate. (4) The fracture toughness of granite shows gradual decay with the increase of tempera- ture. At the same temperature,type I fracture toughness of granite specimens decreases with the increase of heating rate. At ℃,heating rate exerts maximum influence on the fracture toughness of granite.