Abstract

Study of strain localization in geomaterials generally consists of two aspects, the pre-localization regime and the post-localization regime. The former refers to the onset and the orientation of the shear band, which corresponds to the bifurcation theory. The latter deals with the width and the evolution of the shear band. The purpose of this paper is to make a full-range analysis of the shear band in structural level. By comparing the bifurcation conditions in classical continuum an analogical bifurcation condition in micropolar theory is defined. The factors which may affect the shear band orientation in the numerical modeling process are emphasized, and a basic principle of the geometric modeling is concluded. Furthermore, the existing shear band width measurement methods are summarized, and some other more effective methods considering the singularity of the discontinuous surface is suggested. At the last, the ratio between the node distance of the element and the internal length less than 5 is suggested as reasonable choice.

摘要

岩土材料中应变局部化的研究一般包括两个方面，预局部化机制和后局部化机制。前者指的是剪切带的起点和方向，对应于分叉理论。后者涉及剪切带的宽度和演化。本文旨在对结构层面的剪切带进行全方位的分析。通过比较经典连续体中的分岔条件，定义了微极理论中的类比分岔条件。强调了数值模拟过程中可能影响剪切带取向的因素，总结了几何模拟的基本原则。此外，总结了现有的剪切带宽度测量方法，并提出了一些考虑不连续曲面奇异性的其他更有效的方法。最后，建议单元节点距离与内部长度之比小于5为合理选择。