三轴压缩单一裂隙砂岩细观损伤破坏特性CT分析

CT testing on meso-damage propagation mechanism of cracked-sandstone sample under triaxial compression loading

完成了含单一预制裂纹的裂隙砂岩三轴压缩条件下的细观破坏特性CT实时扫描试验。得到了裂纹萌生、发展、宏观裂纹形成、破坏等各阶段的CT图像。结果表明,与完整岩石试样一样,三轴压缩单一裂隙砂岩的破坏过程也可以分为线性发展阶段、细观裂纹萌生及发展阶段、损伤快速发展阶段和峰后损伤加速发展阶段等4个阶段,但是,由于已有裂隙的存在,裂隙岩石的损伤演化速度高于完整岩石的损伤演化速度,已有预制裂纹对新的裂纹的起裂位置及贯通性宏观破坏裂纹的形成具有重要影响,裂隙砂岩试样的扩容量大于完整试样破坏时的扩容量。

The CT real time testing on meso-damage propagation mechanism of crackea-sandstone containing one crack under triaxial compression has been accomplished. The CT images of different stages such as crack birth, development, macro-crack formation and sample failure are obtained. As similar to non-cracked rock sample failure processing, it shows that the failure process of cracked-sandstone under triaxial compressing can be divided into 4 stages including liner-developing, meso-crack birth and developing, damage fast developing and damage speedup developing in post-failure stage. The mesodamage evolution speed of jointed rock sample is larger than that of the rock sample. The pre-crack can seriously affect the location of new crack birth and the formation of connectivity macro-crack. Because of the pre-cracked existing, the expansion speed of the cracked-rock sample under triaxial compression are large than the noncracked rock sample.