Fractography in fracturing process of rocks

岩石压裂过程的研究不仅对岩石力学和构造地质学具有重要意义，而且对脉状矿床、裂隙型油气储层和地热能储层的成因研究和找矿具有重要意义。在岩石三轴压缩试验的各个阶段观察和描述裂缝。为实现薄片裂缝姿态的测量和姿态数据的自动处理，研制了数字通用台。其次，利用井眼镜对高压容器内的压裂过程进行录像。在破裂初期，整个试样区域内的粒间接触处产生平行于中等主应力的晶内微裂纹。沿最大主应力斜面平行发育晶界裂纹或微剪切断裂。在最后阶段，在试样的中心部分产生了一个斜向最大主应力的大剪切断裂，以连接这些微裂纹。

Study of the fracturing process of rocks is very important not only for rock mechanics and structural geology, but also for the researches of the genesis and prospecting of vein-type ore deposits and fissure-filled reservoirs of hydrocarbon and geothermal energy. Fractures are observed and described in the various stages of triaxial compression tests of rocks. Digital universal stage is manufactured to measure the attitude of fractures in thin sections and to process the attitude data automatically. Secondly fracturing process in the high pressure vessel is recorded in video tapes by using the bore-scope. In early stages of fracturing, intragranular micro-cracks parallel to medium principal stress are produced at grain-by-grain contacts in whole area of a test specimen. Grain boundary cracks or micro-shear fractures are also developed parallel to the inclined planes to maximum principal stress. In last stage a major shear fracture oblique to the maximum principal stress is produced in central part of the specimen to connect these micro-cracks.