摘要
岩石的非均质性(矿物夹杂、微裂隙、微孔洞等细观结构)对其非线性力学行为和破坏过程有着显著影响。本文采用无需对复杂细观结构划分网格的快速傅立叶变换(FFT)数值方法,直接获取图像中的像素点作为材料点,准确得到非均质材料的细观结构特征和力学性质的特点,与数字图像处理(DIP)技术有机结合,建立了基于真实细观结构的FFT数值计算方法,模拟了非均质岩石在外荷载作用下的弹塑性变形过程,探究了岩石内部细观结构对非线性力学行为的影响规律与宏观力学性质的内在联系。研究结果表明:基于真实细观结构的FFT模型,能很好地预测不同埋深和不同围压条件下黏土岩的峰前非线性行为和峰值强度,细观结构的形状、大小和分布直接决定了黏土岩内部应力场的分布。研究结论为研究岩石细观结构特征及其非线性力学行为提供了一个重要手段。
Rock heterogeneity(such as mineral inclusions,micro-cracks,micro-voids and other microstructures)significantly affects its nonlinear mechanical behavior and failure process.This paper utilizes the Fast Fourier transform-based(FFT)numerical method which does not require meshing of complex microstructure but directly obtains the microstructure of heterogeneous materials through the pixels of the image.In addition,the method can be naturally combined with digital image processing(DIP).An actualmicrostructure-based FFT method is thereby developed to simulate the elastoplastic behavior of the heterogeneous rocks under external load.The influence of microstructure on the nonlinear behavior is discussed as well as the internal relationship between the microstructure and the macroscopic mechanical proper-ties.The results show that the real-microstructure-based FFT method can well predict the nonlinear be-havior before and after the peak strength of the rocks under different depths and confining pressures.The shape,size and distribution of microstructure directly determine the distribution of stress field in clay rock.The actual-microstructure-based FFT method proposed in this paper can reasonably consider the rock heterogeneity,and provides an important tool for studying the influence of the rock microstructure characteristics on the nonlinear mechanical behavior.
作者
李明耀
彭磊
左建平
王智敏
李绍金
薛喜仁
Li Mingyao;Peng Lei;Zuo Jianping;Wang Zhimin;Li Shaojin;Xue Xiren(School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China)
出处
《矿业科学学报》
CSCD
2022年第4期456-466,共11页
Journal of Mining Science and Technology
基金
国家自然科学基金(11802332)
煤炭资源与安全开采国家重点实验室-北京高等学校卓越青年科学家计划项目联合基金(BJJWZYJH01201911413037,SKLCRSM21LH02)
中国矿业大学(北京)越崎杰出者奖励计划
中央高校基本科研业务费专项资金(2020YQLJ08)。
关键词
快速傅里叶变换法
图像处理
岩石材料
细观力学
非均质性
Fast Fourier Transforms(FFT)method
digital image process
rocks
micromechanics
heterogeneity