石灰岩局部化变形的图像特征  

IMAGE FEATURES OF LOCALIZED DEFORMATION OF LIMESTONE

作　　者：徐金明[1] 韩娜娜[1] 李岩松 

机构地区：[1]上海大学土木工程系,上海200072 [2]上海自然博物馆工程建设指挥部,上海200041

出　　处：《岩石力学与工程学报》2010年第10期2110-2115,共6页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(40972191);上海市教育委员会科研创新项目(09YZ39)

摘　　要：根据室内单轴压缩试验视频图像对石灰岩局部化变形的数字特征进行分析。原始视频在岩石单轴抗压试验时摄得,根据试验荷载-时间关系曲线得到加载阶段的视频图像并转化为计算机易于识别的视频格式,利用粒子图像测速技术得到石灰岩试样表面任意时刻任意位置的位移大小,分析不同荷载作用下既有裂纹端点的变化过程及新生裂隙的萌生和扩展过程,选取单帧图像纹理参数作为石灰岩不同变形状态的数字特征参数,分别使用灰度直方图和灰度共生矩阵得到石灰岩图像数字特征参数随时间的变化过程。结果表明,既有裂隙端点和新生裂隙的局部化变形现象非常明显;可以将平稳变形阶段和急剧变形阶段间的分界点作为局部化变形的起始点并据此作为局部化变形的启动条件;图像纹理特征参数能够较好反映不同荷载阶段的变形状态,可以用于预报局部化变形的起始时刻。由于图像特征反映岩石的变形破坏过程,该方法将为研究岩体地区局部化变形和地质灾害的细观机制提供一条新的研究途径。The digital features of localized deformation of limestone are analyzed by using video images of uniaxial compression test.The original videos were record during the laboratory uniaxial compression test.The video images at loading stage were obtained by using load-time relation curves and converted into the video formats that can be recognized easily by computer.A particle image velocimetry（PIV） technique was used to compute the displacements of surface of limestone specimen in any time and in any location.The change history of tip displacement of the existing fissure was investigated;the processes of initiation and propagation of new fissures were also analyzed.The textural parameters of a single frame were selected as the digital features reflecting the deformation status of limestone.The change processes of these parameters with time were further investigated based on the grayscale histogram and grayscale co-occurrence matrix from video images.The results show that the phenomena of localized deformations of existing and new fissures are much obvious;the dividing point between stable and rapid deformation stages may be used to determinate the start point and to establish the initiate conditions for localized deformations;the textural parameters can reasonably reflect the change in the deformation status of the limestone under different loading stages and may be used to predict the initial time of localized deformations.Due to the reflection of image features on deformation/failure process of intact rocks or rock masses,the methods presented herein may provide a new research way of meso-scale mechanisms of the localized deformation and geological hazards in rock areas.

关 键 词：岩石力学 石灰岩 局部化变形 图像特征 

分 类 号：TU45[建筑科学—岩土工程]