压缩单裂纹圆孔板(SCDC)岩石动态断裂全过程研究  

Research on whole dynamical fracture process of rock using single cleavage drilled compression(SCDC) specimen

作　　者：曹富[1,2] 杨丽萍[2] 李炼[2,3] 刘恩龙 王启智[1,2,3] 

机构地区：[1]水力学及山区河流开发保护国家重点实验室,四川成都610065 [2]地质灾害防治与地质环境保护国家重点实验室,四川成都610059 [3]四川大学土木工程及应用力学系,四川成都610065

出　　处：《岩土力学》2017年第6期1573-1582,1588,共11页Rock and Soil Mechanics

基　　金：高等学校博士学科点专项科研基金(No.201301181130013);地质灾害防治与地质环境保护国家重点实验室开放基金(No.SKLG2016K015)~~

摘　　要：用大直径分离式霍普金森压杆冲击砂岩的压缩单裂纹圆孔板,成功地监测到Ⅰ型动态断裂的全过程。实验中由裂纹扩展计分别纪录了动态起裂、扩展、止裂、和再起裂时刻,采用分形裂纹扩展模型分析曲折裂纹的扩展速度,最后用实验-数值-解析法确定砂岩的动态起裂韧度、动态扩展韧度、动态止裂韧度以及二次动态起裂韧度。动态断裂全过程的实验结果表明:裂纹扩展路径为不规则曲线,此时裂纹动态扩展速度表征的普适函数值会比假设裂纹路径为直线时小;利用分形模型得到更加接近真实的动态扩展韧度;砂岩的动态起裂韧度大于动态止裂韧度;由于初次动态起裂时的裂纹实为人工切槽,而二次动态起裂时为天然形成的裂纹因而非常尖锐,初次动态起裂韧度略大于二次动态起裂韧度。Dynamic experiments were conducted on single cleavage drilled compression （SCDC） specimens of sandstone using large-diameter split Hopkinson pressure bar to obtain the whole dynamic fracturing process of Mode-I crack. A crack propagation gauge was used to measure the key moments of dynamic initiation, propagation, arrest and re-initiation, respectively. A fractal model of crack extension was applied to analyze the propagation speed of a tortuous crack. Finally, we determined the dynamic initiation toughness, dynamic propagation toughness, dynamic arrest toughness, and dynamic re-initiation toughness using the experimental-numerical-analytical method. The results demonstrate that the crack propagation path is torturous in the process of crack propagation. For this irregular curve path, the value of the universal function, which was characterized by the crack propagation velocity, was smaller than that with a straight path. It is found that the dynamic propagation toughness obtained by the fractal model was close to its real value. The dynamic initiation toughness was greater than the dynamic arrest toughness, and the dynamic initiation toughness was slightly greater than the dynamic re-initiation toughness. The reason probably was that the naturally formed crack at the second re-initiation was sharp, while the artificial notch forthe first dynamic initiation was blunt at a certain degree.

关 键 词：动态断裂全过程 各种动态断裂韧度 分形裂纹 二次起裂 压缩单裂纹圆孔板(SCDC) 

分 类 号：TU458[建筑科学—岩土工程] O346.11[建筑科学—土工工程]