掺砾黏土拉伸断裂细观特性研究

发布时间：2018-10-30 12:31

【摘要】：掺砾黏土在高心墙堆石坝工程中的应用越来越广泛,其拉伸断裂特性对心墙的安全至关重要。将掺砾黏土视作四相复合材料,基于图像处理和随机投放建立了考虑真实砾石形态的细观数值模型,结合物理试验的结果验证了其有效性,并分析了掺砾黏土拉伸断裂的宏细观特性。应力位移曲线的宏观非线性是细观非均质性的体现,砾石的掺入大幅减低了抗拉强度,但提高了峰后抗拉性能;土石界面是微裂缝发展的源头,拉伸断裂是一个微裂缝萌生、扩展以至汇集形成宏观裂缝的过程;拉伸断裂发生在一个区域,即断裂过程区,该区域的形成与砾石的随机分布有关。最后,采用数值试验分析了随机砾石投放和掺砾量对掺砾黏土宏细观力学行为的影响。
[Abstract]:The application of gravel clay in high core rockfill dam is more and more extensive, and its tensile fracture characteristics are very important to the safety of core wall. Based on image processing and random placement, a meso-numerical model considering the morphology of real gravel is established, and the validity of the model is verified by the results of physical experiments. The macroscopical characteristics of tensile fracture of gravel-mixed clay are analyzed. The macroscopic nonlinearity of the stress-displacement curve is the embodiment of meso-heterogeneity. The addition of gravel reduces the tensile strength significantly, but improves the tensile strength after the peak. The interface of soil and rock is the source of the development of microcracks, and the tensile fracture is a process of initiation, expansion and accumulation of microcracks to form macroscopic fractures. The tensile fracture occurs in a region, that is, the fracture process area, and the formation of the zone is related to the random distribution of gravel. Finally, the effects of random gravel dropping and the amount of gravel added on the macro-meso-mechanical behavior of gravel-mixed clay are analyzed by numerical experiments.
【作者单位】：清华大学水沙科学与水利水电工程国家重点实验室;
【基金】：国家科技支撑计划(No.2015BAB07B00) 高等学校博士学科点专项科研基金资助课题(No.20120002120028)~~
【分类号】：TV641;TV41

【相似文献】