摘要
采用国际岩石力学协会推荐的人字型切槽巴西圆盘试样(CCNBD)和中心直裂纹三点弯曲试样(NSCB),在RMT-150B试验机上进行了劈裂加载试验,结合声发射仪对比分析了不同尺寸试样的载荷-位移曲线、破坏形态和断裂韧度测试值的差异。结果表明:CCNBD试样的载荷-位移曲线可能出现二次倒拐现象,NSCB试样的载荷-位移曲线峰后直接跌落;两种试样破坏过程中的振铃计数和能量与时间的变化过程与载荷-时间曲线完全对应;NSCB试样测得的大理岩断裂韧度平均值比CCNBD试样测试值偏高4%左右,但试样尺寸较大时,偏高程度更为明显;两种试样都是劈裂加载破坏形式,CCNBD试样在端部可能出现偏离加载直径方向的破坏形式,本研究结果有助于进一步完善和推广ISRM测试岩石断裂韧度的建议方法。
The splitting loading tests of Cracked Chevron Notched Brazilian Disc specimen (CCNBD) and Notch Semi-Circular Bend specimen (NSCB) recommended by International Association of Rock Mechanics were carried out on RMT-150B tester. The load-displacement curve, failure mode and fracture toughness test value of the specimens by different size specimens were compared and analyzed. The result indicates that the load displacement curve of CCNBD specimen may be reversed twice and the load displacement curve of NSCB specimen falls directly after the peak. The ring counting, energy and time variation in the failure process of specimens completely corresponds to the load-time curve. The average fracture toughness of marble measured by NSCB specimens is about 4% higher than that of CCNBD specimens and the higher degree is more obvious when the specimen size is larger. Both types of specimens are fractured under splitting load, and CCNBD specimen may deviate from the direction of loading diameter at the end. The study is helpful to improve and popularize the method of testing rock fracture toughness suggested by ISRM.
作者
赵文峰
张盛
王猛
神文龙
焦振国
ZHAO Wen-feng;ZHANG Sheng;WANG Meng;SHEN Wen-long;JIAO Zhen-guo(School of Energy Science and Engineering,Henan Polytechnic University,Jiaozuo 454001,Henan,China;Collaborative Innovation Center of Coal Work Safety,Jiaozuo 454001,Henan,China;Baidong Coal Industry Co.Ltd.of Datong Coal Mine Group,Datong 037003,Shanxi,China)
出处
《实验力学》
CSCD
北大核心
2020年第4期702-711,共10页
Journal of Experimental Mechanics
基金
国家自然科学基金面上项目(No.51674101,51704098)
河南省重点实验室开放基金(S201605)。
