试样几何参数对岩石断裂韧度影响实验研究
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摘要
将大理岩制备成圆盘试样及半圆盘试样,同时在试样的中心预制一条一定倾角的裂隙,通过变换裂隙倾角制备出不同几何形状的断裂韧度实验试样。基于不同的断裂韧度实验,获取了BD(圆盘试样)实验及SCB(半圆盘试样)实验在不同裂隙几何布置条件下的断裂韧度,分析几何因素对断裂韧度结果的影响。通过分析实验结果可得:实验的几何尺寸及实验加载方式对裂隙的断裂韧度、裂隙起裂角及裂隙的扩展路径有较大的影响;同时,BD实验的断裂韧度强度比SCB实验断裂韧度强度大,并且传统的MTS断裂准则不能很好描述不同裂隙倾角下SCB及BD实验断裂韧度的实验结果,而采用GMTS准则能够很好地预测Ⅰ、Ⅱ型混合断裂韧度实验结果。
The specimens of marble and semi disc were prepared,and a certain inclined fracture was preformed at the center of the specimen. The fracture specimens with different geometries were prepared by changing the dip angle of the fracture. Based on different experiments of fracture toughness,BD( disc specimens) test and SCB( semi disc specimen) fracture toughness in different fracture geometrical arrangement were obtained under the different conditions of experiment,the influence of geometrical factors on fracture toughness results were also analyzed. By analyzing the experimental results,it can be concluded that the size of the experiment and the mode of loading have a great influence on the fracture toughness,the crack initiation angle and the fracture propagation path. At the same time,the fracture toughness strength of BD experiment is larger than that of the SCB experiment,the experimental results of SCB and BD in the experiment of fracture toughness and fracture criterion of traditional MTS is not a good description of the different fracture angle. The GMTS criterion can well predict the experimental results of mixed fracture toughness of Ⅰ and Ⅱ type.
The specimens of marble and semi disc were prepared,and a certain inclined fracture was preformed at the center of the specimen. The fracture specimens with different geometries were prepared by changing the dip angle of the fracture. Based on different experiments of fracture toughness,BD( disc specimens) test and SCB( semi disc specimen) fracture toughness in different fracture geometrical arrangement were obtained under the different conditions of experiment,the influence of geometrical factors on fracture toughness results were also analyzed. By analyzing the experimental results,it can be concluded that the size of the experiment and the mode of loading have a great influence on the fracture toughness,the crack initiation angle and the fracture propagation path. At the same time,the fracture toughness strength of BD experiment is larger than that of the SCB experiment,the experimental results of SCB and BD in the experiment of fracture toughness and fracture criterion of traditional MTS is not a good description of the different fracture angle. The GMTS criterion can well predict the experimental results of mixed fracture toughness of Ⅰ and Ⅱ type.
引文
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[2]崔振东,刘大安,安光明,等.V形切槽巴西圆盘法测定岩石断裂韧度KIC的实验研究[J].岩土力学,2010,31(9):2743-2748.Cui Zhendong,Liu Daan,An Guangming,et al.Research for determining mode I rock fracture toughness KICusing cracked chevron notched brazilian disc specimen[J].Rock and Soil Mechanics,2010,31(9):2743-2748.
[3]尹祥础,颜玉定,李红,等.不同方法测定岩石断裂韧度KIC的研究[J].岩石力学与工程学报,1990,9(4):328-333.Yin Xiangchu,Yan Yuding,Li Hong,et al.Experimental investigation on the measurement of fracture toughness KICof rocks using different methods[J].Chinese Journal of Rock Mechanics and Engineering,1990,9(4):328-333.
[4]朱哲明,王洪山.切口曲率半径对岩石断裂韧度K IC值的影响[J].实验力学,1993,8(1):92-95.Zhu Zheming,Wang Hongshan.Effect of notch root radius on rock fracture toughness K IC[J].Journal of Experimental Mechanics,1993,8(1):92-95.
[5]郑雨天,张兴,石海鱼.岩石断裂韧度测定的研究[J].水利学报,1984(9):19-28.Zheng Yutian,Zhang Xing,Shi Haiyu.Experimental research on fracture toughness of rock[J].Journal of Hydraulic Engineering,1984(9):19-28.
[6]饶秋华,孙宗颀,Li Chunlin,等.剪切盒加载下岩石剪切(Ⅱ型)断裂韧度KIC的测定[J].中南工业大学学报(自然科学版),2001,32(6):563-567.Rao Qiuhua,Sun Zongqi,Li Chunlin,et al.Determination of shear(ModeⅡ)fracture toughness K IC of rock using shear-box test[J].Journal of Central South University of Technology(Natural Science),2001,32(6):563-567.
[7]周绍青,郭少华,李显方.T应力对岩石断裂韧度及扩展路径的影响[J].中南大学学报(自然科学版),2009,40(3):797-802.Zhou Shaoqing,Guo Shaohua,Li Xianfang.T-stress's impact on rock's fracture toughness and propagation path[J].Journal of Central South University(Science and Technology),2009,40(3):797-802.
[8]Ayatollahi MR,Aliha MRM.Wide range data for crack tip parameters in two disc-type specimens under mixed mode loading[J].Computational Material Science,2007,38(4):660-670.
[9]Fowell RJ.The use of the cracked Brazilian disc geometry for rock fracture investigations[J].International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts,1994,31(6):571-579.
[10]Erdogan F,Sih GC.On the crack extension in plates under plane loading and transverse shear[J].Transactions ASME.Journal of Basic Engineering,1963,85:519-525.
[11]Williams ML.On the stress distribution at the base of a stationary crack[J].Journal of Applied Mechanics,1957,24:109-114.
[12]Schmidt RA.A microcrack model and its significance to hydraulic fracturing and fracture toughness testing[C].In:Proceedings of the 21st U.S.Rock mechanics syposium,Missouri,Rolla,27-30May 1980:581-590.