北山花岗岩热损伤力学特性试验研究

Experimental study of mechanical properties of Beishan granite's thermal damage

为了研究北山花岗岩热损伤力学特性,选取甘肃北山坑探设施钻爆施工后的花岗岩试件,分别开展了高温作用后的三轴压缩试验和实时高温状态下的单轴压缩试验,分析了各个试验条件下的典型应力-应变曲线和声发射特征,对比研究了其强度参数和变形参数损伤劣化规律.结果表明:高温作用后的三轴压缩试验,在相同围压条件下,北山花岗岩抗压强度、弹性模量随着作用温度的升高呈现出先增加后减小的趋势.实时高温状态下的单轴压缩时,随着温度的升高,抗压强度、弹性模量呈下降趋势.相同温度条件下,实时高温状态下北山花岗岩单轴抗压强度、弹性模量均小于高温作用后的单轴抗压强度、弹性模量.

In order to study thermal-damaged mechanical properties of granite,granite specimens after drilling and blasting construction of exploration tunnel in Beishan,Gansu were selected,triaxial compression tests after high temperature treatment and uniaxial compression tests under real-time state of high temperature condition were carried out respectively.The typical stress-strain curves and acoustic emission features were analyzed,the damage deterioration law of strength parameters and deformation parameters were compared.The results show that the compressive strength and elastic modulus of the Beishan granite increase first and then decrease with the increase of temperature under the same confining pressure during triaxial compression after high temperature.The compressive strength and elastic modulus decrease with the increase of temperature under the condition of uniaxial compression at real-time state of high temperature.Under the same temperature condition,the uniaxial compressive strength and elastic modulus of Beishan granite under real-time state of high temperature are less thanthat of granite after high temperature treatment.