摘要
结合使用专用三轴压力仪与CT扫描仪,对砂岩和粉砂岩分别进行压缩试验并获得了系列CT图像。发现单轴压缩和三轴压缩时岩石试件均经历压密、扩容、CT尺度裂纹萌生、扩展、扩张、贯通和岩石宏观破坏阶段。在压密阶段和扩容阶段,CT图像无明显变化。采用密度损伤增量定量描述细观裂纹演化的集合效应。在CT尺度裂纹演化阶段,从CT图像出发描述裂纹的空间位置、形态、运动方向分析CT尺度裂纹演化对于岩石变形和强度的影响。裂纹模式图可揭示CT裂纹演化的规律。CT裂纹演化的基本特点是扩展与扩张的交替性。三轴条件下CT裂纹与主应力夹角较大,裂纹面较平直,裂纹扩张困难,呈现剪切破坏特点。
Compression tests on sandstone and saltstone are made using special triaxial compression equipment and Xray CT scanner with a series of CT images obtained. It has been found that when uniaxial and triaxial compression are conducted,rock samples experience the stages of condensation, dilatancy, precrack propagation,expansion,runningthrough and rock macrofailure stages of CT scales. At the stages of condensation and dilatancy there is no obvious change in CT images, so that the change in the density of rock is described by the density damage increment value. At the stages of CT scale crack evolution the location,morphology and kinematic direction of CT scale crack are analyzed to evaluate the effect on deformation and strength of rock samples. The CT crack evolution law can be demonstrated by the mode of crack.The basic character of CT crack evolution is in turn between propagation and expansion. Under triaxial condition the CT crack has a bigger angle to the major stress and a even plane. It's difficult to expand for the CT crack and the rock sample has a shear failure mode.
出处
《西安理工大学学报》
CAS
2003年第2期115-119,共5页
Journal of Xi'an University of Technology
基金
国家自然科学基金资助项目(10172071)
陕西省教育厅专项科研计划项目(00JK218
01JK146)。
关键词
岩石
细观裂纹
分岔
密度损伤增量
围压
rock
meso-crack
bifurcate
density damage increment
confining pressure
