为了探究实时高温条件下岩石试样的拉伸试验和全过程声发射特性,采用MTS810电液伺服试验系统,进行了不同实时温度下核废料预选区北山花岗岩试样巴西劈裂试验,比较分析不同温度(25～1 000 ℃)下北山花岗岩宏微观的破坏特征、荷载-位移曲线、抗拉强度以及全过程声发射特征随温度的演化规律等。研究结果表明:随着温度的升高,北山花岗岩形成的裂缝越来越多,晶间裂纹的裂缝孔径逐渐增大,T> 400 ℃时形成明显的穿晶裂缝,失效模式也从脆性的拉伸破坏变为延性,呈Y型破裂模式;荷载-位移曲线形状由“下凹”型向“上凸”型转变,实时高温下北山花岗岩抗拉强度整体呈下降趋势,这种随温度的劣化趋势却表现出较强的阶段性特征;达到峰值荷载之前声发射(AE)事件存在平静期,随着温度的增加,这种平静期阶段变得越来越不明显,同时峰值振铃计数率逐渐减小。研究成果可供深部地下实验室建设和数值模拟提供参考。
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.
关键词
电镜扫描 /
实时高温 /
北山花岗岩 /
劈裂试验 /
声发射
Key words
electron microscope scanning(SEM) /
real-time high temperature /
Beishan granite /
splitting tests /
acoustic emission
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 孙 强,张志镇,薛 雷. 岩石高温相变与物理力学性质变化. 岩石力学与工程学报,2013,32(5):935-942.
[2] 方新宇, 许金余, 刘 石,等. 高温后花岗岩的劈裂试验及热损伤特性研究. 岩石力学与工程学报, 2016,35(增刊1):2687-2694.
[3] 苏海健, 靖洪文, 赵洪辉,等. 高温处理后红砂岩抗拉强度及其尺寸效应研究. 岩石力学与工程学报, 2015,34(增刊1):2879-2887.
[4] 左建平,周宏伟,刘瑜杰. 不同温度下砂岩三点弯曲破坏的特征参量研究. 岩石力学与工程学报,2010,29(4):705-712.
[5] 左建平,谢和平,刘瑜杰,等. 不同温度热处理后砂岩三点弯曲的断裂特性. 固体力学学报,2010,31(2):119-126.
[6] YIN T B, SHU R H, LI X B, et al. Comparison of Mechanical Properties in High Temperature and Thermal Treatment Granite. Transactions of Nonferrous Metals Society of China, 2016, 26(7):1926-1937.
[7] GANNE P, VEROORT A, WEVESS M. Quantification of Pre-peak Brittle Damage: Correlation Between Acoustic Emission and Observed Micro-fracturing. International Journal of Rock Mechanics and Mining Sciences,2007,44(5):720-729.
[8] 翟松韬,吴 刚,张 渊,等. 高温作用下花岗岩的声发射特征研究. 岩石力学与工程学报, 2013, 32(1):126-134.
[9] 翟松韬, 吴 刚, 孙 红,等. 高温下大理岩的声发射特性试验研究. 岩土工程学报, 2013, 35(增刊2):177-183.
[10] 王德咏,吴 刚,葛修润. 高温作用后石灰岩受压破坏过程的声发射试验研究. 上海交通大学学报, 2011,45(5):743-748.
[11] 孟 磊, 王宏伟, 李学华,等. 含瓦斯煤破裂过程中声发射行为特性的研究. 煤炭学报, 2014, 39(2):377-383.
[12] 武晋文,赵阳升,万志军,等. 中高温三轴应力下鲁灰花岗岩热破裂声发射特征的试验研究. 岩土力学,2009,30(11):3331-3336.
[13] 陈世万, 杨春和, 刘鹏君,等. 热损伤后北山花岗岩裂隙演化及渗透率试验研究. 岩土工程学报, 2017, 39(8):1493-1500.
[14] 吴 刚,翟松韬,孙 红,等. 高温下盐岩的声发射特性试验研究. 岩石力学与工程学报,2014, 33(6):1203-1211.
基金
国家自然科学基金项目(51174196);国家青年自然科学基金项目(51204168)
PDF(1926 KB)
