基于微裂纹发育特性的大理岩特征强度数值模拟研究

发布时间：2018-02-25 18:43

本文关键词： 微裂纹起裂强度损伤强度离散元主成分分析　出处：《岩土力学》2017年01期 　论文类型：期刊论文

【摘要】：为获取锦屏大理岩的特征强度及破坏过程中损伤演化规律,运用PFC~(3D)模拟大理岩试样并进行单轴、三轴压缩试验,以微裂纹的形态和数量的变化特征来确定大理岩的起裂和损伤强度。当微裂纹数量为峰值强度下微裂纹数量的0.1%,认为出现初始损伤,此时应力为大理岩的起裂强度。单轴压缩试验中,从裂纹形态上观察,将出现基本破裂面的应力定义为损伤强度。三轴压缩试验中,从裂纹数量上观察,将出现裂纹非稳定增长阶段时的应力定义为损伤强度。分析不同阶段出现微裂纹的位置实现了对微裂纹的定位,分析不同模型微裂纹增长量的变化,实现了对微裂纹稳定和非稳定增长的界定,补充了声发射的不足。对比PFC~(3D)模拟和实验室试验得出的大理岩的特征强度,两者特征强度曲线的拟合函数相近。这说明运用PFC~(3D)模拟确定大理岩的起裂强度、损伤强度的方法是一种合理的方法,微裂纹的研究对揭示脆性岩石强度破坏机制具有重要意义。
[Abstract]:In order to obtain the characteristic strength of Jinping marble and the law of damage evolution in the process of failure, the specimen of marble was simulated by using PFCf3D and the uniaxial and triaxial compression tests were carried out. The crack initiation and damage intensity of marble are determined by the variation characteristics of the shape and number of microcracks. When the number of microcracks is 0.1 of the number of microcracks at the peak strength, the initial damage is considered to occur. In the uniaxial compression test, the stress of the basic fracture plane is defined as the damage strength, and in the triaxial compression test, the number of cracks is observed. The stress at the stage of unstable growth of crack is defined as the damage strength. The location of microcrack and the variation of growth quantity of microcrack in different model are analyzed by analyzing the location of microcrack in different stage. The definition of stable and unstable growth of microcracks is realized, and the deficiency of acoustic emission is supplemented. The characteristic strength of marble obtained from simulation and laboratory tests is compared. The fitting function of the two characteristic strength curves is similar, which indicates that the method of determining the fracture initiation strength and damage strength of marble by PFCf3D simulation is a reasonable method, and the study of micro-cracks is of great significance to reveal the failure mechanism of brittle rock strength.
【作者单位】：华中科技大学土木工程与力学学院;
【基金】：国家自然科学基金(No.51278391)~~
【分类号】：TU45

【相似文献】