基于DIC技术的含不同节理密度类岩石试件破裂机制研究  

Fracturing mechanism of rock-like specimens with different joint densities based on DIC technology

作　　者：齐飞飞 张科 谢建斌[2,3] QI Fei-fei;ZHANG Ke;XIE Jian-bin(Faculty of Electric Power Engineering,Kunming University of Science and Technology,Kunming,Yunnan 650500,China;Faculty of Civil and Architectural Engineering,Kunming University of Science and Technology,Kunming,Yunnan 650500,China;Department of Civil Engineering,Yunnan University,Kunming,Yunnan 650500,China)

机构地区：[1]昆明理工大学电力工程学院,云南昆明650500 [2]昆明理工大学建筑工程学院,云南昆明650500 [3]云南大学土木工程系,云南昆明650500

出　　处：《岩土力学》2021年第6期1669-1680,共12页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.11902128,No.41762021);云南省应用基础研究计划项目(No.2019FI012)。

摘　　要：为研究节理密度对岩体强度特征及破坏模式的影响,以石英砂和呋喃树脂为打印基材,采用3D砂型打印技术制备含有不同节理密度的类岩石试件。对3D砂型打印试件进行单轴压缩试验,采用数字图像相关(DIC)方法进行非接触式全场变形测量,从细观力学角度定量分析裂纹萌生、扩展以及贯通行为。试验结果表明:3D砂型打印完整试件的应力-应变曲线形态、压拉强度比与真实岩石相似,属于一种类岩石材料;不同节理密度试件的应力-应变曲线变化过程大致相似,可划分为初始压密、线弹性变形、破裂发展以及残余强度4个阶段;试件力学参数随着节理密度εf的增加而减小,两者之间呈指数衰减关系;通过计算试件表面应变场和位移矢量分布,发现试件变形场分布、裂纹扩展演化均与节理密度密切相关;随着节理密度的增大,试件破坏模式由轴向拉伸破坏(εf=0.280%)过渡到混合破坏(εf=1.193%),最后转变为拉贯通带破坏(εf≥1.712%),而当节理密度超过阈值2.739%,拉贯通带内的块体发生转动,重现了书斜式断层旋转这类地质构造。In order to study the influence of joint density on the strength characteristics and failure modes of rock mass, the rock-like specimens with different joint densities were prepared by using 3D sand printing, with the quartz sand and furan resin being employed as the printing materials. The uniaxial compression test was performed on the 3D sand printed specimens, and the digital image correlation(DIC) method was used as a non-contact technique to monitor the full-field deformation. The crack initiation, propagation and coalescence behaviors were quantitatively analyzed from the micromechanics point of view. The results show that the shape of stress-strain curve and the compressive-to-tensile strength ratio of 3D sand printed intact specimen are similar with those of the natural rock, which can be grouped as a rock-like material. The variation processes of stress-strain curves with different joint densities are similar, and can be divided into initial compaction, linear elastic deformation, crack development and residual strength stages. The mechanical properties of specimens decrease with the increase of joint density ef, and the relationship can be expressed as exponential decay functions. By calculating the strain field and displacement vector distribution on the specimen surface, the deformation field distribution and crack propagation of the specimen are found to be closely related to the joint density. The failure mode shifts from axial tension failure(εf = 0.280%) toward mixed failure(εf = 1.193%) and then to tensile coalescence band failure(εf ≥ 1.712%) as the flaw density increases. When the joint density is greater than or equal to 2.739%, the block rotation appears in the tensile coalescence band, and the bookshelf faulting with block rotation is reproduced.

关 键 词：岩石力学 节理密度 3D打印 破坏模式 数字图像相关(DIC)方法 位移场 

分 类 号：TU452[建筑科学—岩土工程]