单轴压缩条件下土石混合体开裂特征研究

发布时间：2018-05-25 16:13

本文选题：土力学 + 土石混合体　；参考：《岩石力学与工程学报》2015年S1期

【摘要】：土石混合体作为一种物质成分和内部结构特征极为复杂的多相多组分散粒材料,其破坏是一个复杂的结构变化过程。应用CT试验和数值模拟方法研究土石混合体的变形破坏特征,指出开裂是土石混合体区别于其他地质体变形破坏的一个显著特征。土石混合体破坏的根本原因是块石与土体的弹性不匹配和土石界面的差异滑动,破坏的实质是内部裂纹产生、扩展、互锁和贯通的过程。通过对土石混合体开裂机制的研究得出以下结论:(1)基于CT试验的变形特征分析表明试样、块石包裹体及其邻近土体三个感兴趣区域的CT数随应力水平的增加而不断减小,且块石包裹体的CT数变化较土体更为敏感。(2)数值模拟结果表明试样破坏过程经历了土石结合裂纹的萌生、慢裂、快裂致贯通破坏的过程。土石接触面是最薄弱的部位,荷载作用下界面差异滑动引起裂纹的产生,随后裂纹沿块石边界缓慢扩展直至扩展到土体中,受块石形状及分布的影响,裂纹会出现局部化发展和互锁现象。大量裂纹在土体中快速扩展聚集引起试样的破坏。(3)土石混合体的破坏具有渐进性的过程,破坏可分为三级:一是土石界面的开裂,二是土体中裂纹的扩展、聚集和贯通并且最终导致试样的破坏,三是针对软弱的片岩块石的穿石破坏。
[Abstract]:Soil-rock mixture is a kind of multiphase and multi-group dispersed material with extremely complex material composition and internal structure. Its failure is a complicated process of structure change. The deformation and failure characteristics of soil-rock mixture are studied by CT test and numerical simulation, and it is pointed out that cracking is a remarkable characteristic of soil-rock mixture which is different from other geological bodies in deformation and failure. The fundamental cause of soil-rock mixture failure is the elastic mismatch between rock and soil and the differential sliding between soil and rock. The essence of the failure is the process of internal crack generation, propagation, interlocking and penetration. By studying the cracking mechanism of soil-rock mixture, the following conclusions are drawn: (1) based on the analysis of deformation characteristics of CT test, it is shown that the CT number of the three regions of interest in the block inclusion and its adjacent soil decreases with the increase of stress level. The results of numerical simulation show that the failure process of the specimen has experienced the process of initiation, slow crack and fast crack of soil-rock bond crack. The soil and rock contact surface is the weakest part, and the crack is caused by the differential sliding of the interface under the load, and then the crack spreads slowly along the boundary of the block and then extends to the soil, which is affected by the shape and distribution of the block stone. Localized development and interlocking will occur in cracks. A large number of cracks in the soil mass caused by the rapid propagation and aggregation of the specimen failure. 3) the failure of the mixed soil and rock has a gradual process, the failure can be divided into three levels: first, the cracking of the interface between soil and stone, the second is the crack propagation in the soil. Aggregates and penetrates and ultimately leads to the failure of the specimen, and the third is the penetrating failure of the weak schist.
【作者单位】：中国科学院地质与地球物理研究所页岩气与地质工程重点实验室;
【基金】：国家自然科学基金资助项目(41227901,41330643) 中国科学院战略性先导科技专项B类(XDB10030000)
【分类号】：TU43

【参考文献】