单轴压缩载荷作用下双裂隙扩展的CT扫描试验

由于精选后的陶瓷材料与岩石性质相似,因此选择陶瓷作为基本材料制作中部含2条圆币状裂隙的试件,进行单轴压缩荷载作用下的CT实时扫描试验,研究试件内双裂隙的扩展和损伤演化规律。采用3种不同区域划分方案,通过CT数、CT方差和CT图像的对比,分析上、下裂隙及岩桥区域不同的扩展状况。分析表明,上裂隙区域一直以压密为主,扩展很小,对试件破坏影响较小;下裂隙区域扩展剧烈,最终形成了宏观裂纹,对试件的破坏影响较大;当上下裂隙之间的中心距离等于4倍的裂隙半径时,裂隙的扩展过程将与裂隙自身参数有关,几乎看不出裂隙之间的相互作用。

CT real-time scanning tests on double cracks propagation under uniaxial compression

Because ceramics is similar to rock in mechanism, ceramics is selected to precut the test specimens with artificial double initial disk-like cracks. The CT real-time scanning tests of the specimens are carried out to study the propagation and damage mechanism of the 3D crack under uniaxial compression. From the comparative analysis of CT values, CT variances and CT images in three different manifold areas, the different propagation laws in areas of up-crack, down-crack and rock bridge are obtained. Firstly, in the up-crack areas, compression and densification are dominant and growth is subordinate; so up-crack has little influence on the damage of the specimen. Secondly, the down-crack propagates greatly, visible wings appear and macro-cracks join together finally, which has great influence on the failure of the specimen. Thirdly, when the center distance between two cracks equals to the 4 times of the crack radius, the propagation process of the crack is related to its parameters; and the interaction between the dual cracks can be omitted.