剪切局部化是岩石变形破坏的前兆，Mohr-Coulomb（MC）强度准则在用于地质灾害研究时，不能解释岩石的剪切局部化现象。本项目拟在细观结构层次研究岩石变形失稳的剪切局部化特征，用剪切带宽度对MC强度准则进行修正。首先，基于已做的研究成果及材料细观物理机制，运用量纲分析，推导含剪切带宽度的MC强度准则，确定剪切带宽度与材料微细观结构参数的关系。其次，利用粒子图像测速技术（PIV）、扫描电镜观测（SEM）和声发射（AE）监测定位结合，研究不同结构类型岩样在各种加载条件下的剪切带特征，建立“准确”测量剪切带宽度的实验方法。最后，研究剪切带宽度的影响因素。结合力学实验及岩石细观结构的系统分析，确定与岩石细观结构相关的各因素对剪切带宽度的影响，建立它们与剪切带宽度之间的定量关系，确定岩石破坏的声发射前兆。修正的MC强度准则，可以更好地解释各种相关的地质灾害现象，适用于更为复杂的工程地质条件。

It is known to all that shear localization is a precursor to rock failure. The famous Mohr-Coulomb (MC) failure criterion, however, cannot explain this phenomenon when it was applied to relative geology disasters’ investigations. This application aims to a new modification of MC criterion by shear band width through a thorough survey of shear localization band during rock deformation and destabilization on meso-structure level. The new MC criterion, concluding the width of shear band, is firstly held out based on previous results by myself and meso-physical mechanism of material, with dimensional analysis. It also studies relationship between the shear band width and rock’s meso-structure. Secondly, the applicant is about to find a “precise” method to measure the shear band width. To accomplish this target, it carries out series experiments of rocks of all kinds and under different loading conditions, with width observations by methods such as particle image velocimetry (PIV), scanner of electronic microscope (SEM) and the monitoring and localization of acoustic emission (AE). Finally, factors that influenced shear band width are studied. Based upon mechanical experiments and a systematical investigation to rock’s meso-structure, it is looking for factors that influenced the shear band width through meso-structure and founding their quantitative relation with shear band width. It can be help to find the AE precursor of rock failure. The new modified MC criterion can give a more reasonable explanation to relative phenomenon of geology disasters and be applicable to more complex engineering geological conditions.