基于数字图像技术的含双裂隙类岩石试样力学特性细观研究
投稿时间:2019-07-24  修订日期:2020-09-01  点此下载全文
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作者单位E-mail
李建旺 北京科技大学 金属矿山高效开采与安全教育部重点实验室 1269619449@qq.com 
基金项目:中央高校基本科研业务费专项资金资助项目(编号:No. FRF-TP-18-016A3)
中文摘要:岩石破坏过程中裂纹孕育演化规律及分布模式是解决岩石破坏问题的关键所在,而裂隙作为一种典型的岩石缺陷,与岩石的宏观力学状态和结构破坏特性之间有着密切的联系。采用数字图像技术(DIC)及颗粒流程序(PFC),研究了单轴压缩状态下含双裂隙类岩石试样破坏全过程,得到了试样破坏过程中观测面全场应变和位移的演化过程以及裂纹发展、微破裂数等特性。研究表明:(1)当载荷到达一定阶段,预制裂隙两端首先出现明显的微破裂区,其形状近似椭圆,开始形成宏观Ⅰ型裂纹(翼形张拉裂纹)。(2)随着载荷的增大,微破裂聚集,裂隙端部开始形成宏观Ⅱ型裂纹(剪切裂纹),并与Ⅰ型裂纹一起持续发育直至试样破坏。(3)预制裂隙左、右两侧和上下两侧的X和Y方向位移量差别较大,X方向位移量在两条预制裂隙的右边为正值,左边为负值;Y方向位移量自固定端(下端)向加载端呈由大到小呈梯度分布。
中文关键词:岩石力学  数字图像技术  颗粒流  单轴压缩  裂纹扩展
 
Meso research on the mechanical properties of rock specimens with double pre-existing fissures based on digital image correlation
Abstract:The cracks initiation and evolution and distribution patterns in rock failure process are the key to solve the rock failure problems. As a typical rock defect, fissures are closely related to the macroscopic mechanical state and structural damage characteristics of rocks. Using digital image correlation (DIC) and particle flow code (PFC), we studied the whole process of fracture of rock specimens with double pre-existing fissures under uniaxial compression. And we obtained the evolution process of the strain and displacement of the entire surface of the observation surface during the fracture of the specimen, as well as the development of sample crack and the number of micro-fracture. The main findings are: (1) When the load reaches a certain stage, the first micro-cracks appear at both ends of the pre-existing fissures, and its shape is similar to the ellipse. Macro-I-type cracks (wing-type tensile cracks) begin to form. (2) With the increase of the load, the micro-fracture gathers, the macroscopic type II cracks (shear cracks) begin to form at the ends of the pre-existing fissures, and continue to develop with type I cracks until the specimen was destroyed. (3) The X, Y direction displacements of the left and right sides of the pre-existing fissures and the upper and lower sides are very different. The displacement in the X direction is positive on the right side of the two pre-existing fissures and negative on the left side; the displacement in the Y direction from the fixed side (lower) to the load side is from the largest to the smallest gradient distribution.
keywords:rock mechanics, digital image correlation, particle flow code, uniaxial compression, crack propagation
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