实时高温下北山花岗岩劈裂试验及声发射特性  

Splitting Tests and Acoustic Emission Characteristics of BeishanGranite under Real-time High Temperature

作　　者：闵明 张强[1] 蒋斌松[1] 李全信 王军鹏 MIN Ming;ZHANG Qiang;JIANG Bin-song;LI Quan-xin;WANG Jun-peng(State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, China;Zhengzhou Engineering Co., Ltd., China Railway Seventh Group, Zhengzhou 450000, China)

机构地区：[1]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116 [2]中铁七局集团郑州工程有限公司,郑州450000

出　　处：《长江科学院院报》2020年第3期108-113,共6页Journal of Changjiang River Scientific Research Institute

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)。

摘　　要：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(25~1000℃)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。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(25-1000℃)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 

分 类 号：TU45[建筑科学—岩土工程]