双交叉裂隙岩桥相互作用与破坏行为试验研究  

Experimental study on rock bridges interaction and failure characteristics of double-cross-flaw

作　　者：陈康 邵亚建 王酉钰 马国伟 CHEN Kang;SHAO Yajian;WANG Youyu;MA Guowei(School of Civil and Transportation Engineering,Hebei University of Technology,Tianjin 300401,China)

机构地区：[1]河北工业大学土木与交通学院,天津300401

出　　处：《实验力学》2023年第1期81-90,共10页Journal of Experimental Mechanics

基　　金：国家自然科学基金(52104124,51627812,U1965204)。

摘　　要：双交叉裂隙是工程岩体中构成断续交叉裂隙的基本单元。裂隙几何参数的变化,会带来裂隙之间岩桥组合形态的改变,并形成岩桥相互作用,对双交叉裂隙的起裂、扩展、贯通及断裂产生直接影响。本文以光敏树脂3D打印技术制备不同次裂隙长度的双交叉裂隙试样,并低温处置使其脆化;开展单轴压缩试验以获得试样的力学性能,利用DIC (Digital Image Correlation,数字图像相关技术)分析试样的变形行为,采用高速摄像机捕捉裂纹萌生和裂隙扩展过程。结果表明,随次裂隙长度的增加,双交叉裂隙试样的峰值强度呈先增大后减小的趋势;试样压缩破坏过程中,最短岩桥(主导岩桥)的两端最先形成应力集中,主导着初始裂纹的形成;尖端裂纹的扩展路径主要受到剪切路径的影响,而剪切路径随加载进程动态变化,由外侧向主导岩桥位置逐步靠拢,控制着次生裂纹的扩展角度。A double-cross-flaw is the basic unit of non-persistent cross joints in the engineering rock mass. The change of the geometric parameters of the flaws brings about the change in the rock-bridge combination, and forms the rock-bridge interaction, which has a direct impact on the initiation, expansion, penetration, and failure of the double-cross-flaw. In this paper, double-cross-flaw specimens with different minor-flaw lengths were prepared by 3D printing with photosensitive resin, and treated at low temperatures to make them brittle. The uniaxial compression test was carried out to obtain the mechanical properties of the specimen, the deformation behavior of the specimen was analyzed by DIC(Digital Image Correlation), and the crack initiation and propagation process were captured by a high-speed camera. The results show that with the increase of the minor-flaw length, the peak strength of the double-cross-flaw specimen showed a trend of increasing first and then decreasing. During the compression failure process of the specimen, the two ends of the shortest rock bridge(or the dominant rock bridge) were the first to generate stress concentration, which dominated the formation of the initial crack. The propagation path of the tip crack is mainly affected by the shear path, and the shear path changes dynamically with the loading process, that is, it gradually moves closer to the dominant rock bridge position from the outside, which controls the propagation angle of the secondary crack.

关 键 词：交叉裂隙 力学行为 破坏模式 3D打印 DIC分析 

分 类 号：TU45[建筑科学—岩土工程]