高温水冷玄武岩微观机理及物理力学特性分析

Analysis of Microscopic Mechanism and Physico-Mechanical Properties of High Temperature-Water Cooled Basalt

为研究高温水冷对玄武岩物理力学特性的影响,对常温(25℃)和经历高温(100℃、300℃、450℃和600℃)水冷处理后的玄武岩试样开展物理测试试验、静态单轴压缩试验、X衍射及电镜扫描试验,分析了高温水冷后试样的微观损伤机理以及试样物理力学特性与温度的相关性。结果表明:高温水冷并未改变玄武岩主要的矿物成分,但对其相对含量有所影响;温度梯度越大,热冲击导致的内部裂纹越多,当温度升至600℃时,微观结构出现韧窝破裂形式;随着温度的升高,试样逐渐由灰绿色转变为红色,质量损失率不断增大,纵波波速不断减小,应力应变曲线逐渐变平缓,峰值强度和弹性模量则呈劣化趋势,且劣化程度逐渐加剧;在高温水冷与荷载耦合作用下,试样总损伤变量演化曲线随温度的升高逐渐变缓,表明试样逐渐由脆性转变为塑性。

In order to study the effect of high temperature-water cooling on the physical and mechanical properties of basalt,physical test,static uniaxial compression test,X-ray diffraction and electron microscope scanning test were carried out on basalt samples after water cooling at room temperature(25℃)and high temperature(100℃,300℃,450℃and 600℃).The micro damage mechanism of samples after high temperaturewater cooling and the correlation between physical and mechanical properties of samples and temperature were analyzed.The results show that high temperature-water cooling does not change the main mineral components of basalt,but has an effect on its relative content;The larger the temperature gradient is,the more internal cracks are caused by thermal shock.When the temperature rises to 600℃,the dimple fracture appears in the microstructure.When the temperature is increase,the samples show the change from gray green to red,the enhancing of mass loss rate,the weakening of longitudinal wave velocity,the slowing down of stress-strain curve,the deterioration trend of peak strength and elastic modulus,and the deterioration degree gradually intensifies;Under the coupling action of high temperature water cooling and load,the evolution curve of the total damage variable of the specimen gradually slows down with the increase of temperature,indicating that the specimen gradually changes from brittle to plastic.