摘要
介绍数字图像处理的基本过程,根据其技术原理编写程序,实现由实拍数字图像直接生成颗粒流模型,为土石混合体力学行为的颗粒流模拟提供新的建模方法。利用该方法,采用PFC2D程序对土石混合体(SRM)进行双轴压缩试验的数值模拟,并与均质土体的试验结果相比较。结果显示,一定碎石含量的土石混合体试样其应力–应变关系呈现出台阶状分布的特征,第一平台段所对应的主应力差基本反映土颗粒的屈服强度;之后强度的提高则与碎块石存在形成的应变硬化现象相关。数值模拟反映出的规律与现场试验结果一致。通过分析土石混合体试样的破坏形态,发现其破坏过程与形态要比均质土体复杂的多,由于碎块石的存在,破裂面往往不规则,不像均质土体那样呈明显的条带状破坏。
The basic process of digital image processing technique is described firstly. Based on the technique, a program is designed to directly set up particle flow model from digital image, which provides a new modeling method for particle flow simulation about mechanical behaviors of soil and rock mixtures（SRM）. Then, using the proposed modeling method, a series ofbiaxial tests are simulated by the particle flow code in 2 dimensions（PFC2D）. After that, the results of these biaxial tests for SRM are compared with those of homogeneous soils. The results show that the stress-strain curve of SRM has a feature of stepwise; and the differential value between principal stresses at the first step basically corresponds to the yield strength of soil; and the strength increase is due to strain hardening phenomenon caused by gravel, which is consistent with the field test result. Finally, the failure mode of SRM is studied; and the results show that there is a great difference comparing to that of homogeneous soils; and the failure zone is irregular for SRM; but when the homogeneous soil fails, there exists a banded shear zone.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2010年第3期477-484,共8页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(40772193
50539110)
关键词
岩土力学
土石混合体
数字图像处理
颗粒流模型
细观力学
屈服强度
应变硬化
rock and soil mechanics
soil and rock mixtures（SRM）
digital image processing
particle flow model
mesomechanics
yield strength
strain hardening
