关键词: 电镜扫描, 实时高温, 北山花岗岩, 劈裂试验, 声发射

Abstract: In an attempt to obtain the acoustic emission characteristics of rock in the whole process of tensile test under real-time high temperature, Brazil splitting test was performed on Beishan granite using MTS810 electro-hydraulic servo test system. The variations of macro-and-microscopic failure characteristics, load-displacement curves, tensile strength, and acoustic emission(AE) characteristics with temperature(T) of Beishan granite under different temperatures (25-1 000 ℃) were compared and analyzed. With the climbing of temperature, an increasing number of cracks are found in Beishan granite. The crack aperture of intergranular cracks increased gradually, and obvious transgranular cracks are observed at T > 400 ℃, with the failure mode transforming from brittle tensile failure to ductile fracture, displaying a Y-shape. The shape of load-displacement curve varied from concave to convex. The tensile strength of Beishan granite under real-time high temperature declined in general, but this deterioration trend with temperature was evidently staged. Before peak load, AE event was quiet, which, nevertheless, became more active with the rising of temperature, and meanwhile the peak ring count rate decreased gradually.

Key words: electron microscope scanning(SEM), real-time high temperature, Beishan granite, splitting tests, acoustic emission