多孔岩石局部化变形的应力分布及演化规律的数值模拟研究

The formation and development of strain localization of porous rocks is the initial stage of rocks macroscopic instability,and the study of their stress behavior characteristics is of great significance for engineering safety construction.At present,a systematic theory has been formed for the study of the strain localization of porous rocks under stress,but there is still a lack of detailed micro evidence on the dynamic process of microscopic fracture,the distribution and evolution characteristics of stress field.Therefore,in this study,taking the Leitha limestones as the research object,we have conducted the conventional triaxial compression experiment,and observed the strain localization and fracture nucleation process of the porous rocks in real time by using dynamic CT imaging technology.Based on the CT data obtained as the modeling file,discrete elements method(DEM)simulation was used to analyze the evolution of strain localization of porous limestones under stress from a microscopic perspective.The results show that the generation and expansion process of the model's strain localization is basically consistent with the experimental data of stress behavior,and there is a high stress concentration around the pores before strain localization formation of porous rocks.In this paper,the stress distribution and evolution of pore collapse and grain crushing of porous rocks under stress are further systematically expounded.