基于CT扫描的煤岩非均质特征及其重建模型数值分析

Heterogeneous characteristics of coal based on CT scanning and numerical analysis of its reconstruction model

为研究矿物结构在空间内的几何形态、尺寸和分布对煤岩的宏观力学行为及变形破坏特征的影响,利用CT扫描和三维重建技术建立煤岩矿物结构的三维可视化模型,统计分析不同等效直径范围内矿物结构特征,在此基础上构建包含4种不同等效直径矿物结构的非均质数值模型,并对其进行单轴压缩模拟分析。研究结果表明:粒径较小的矿物结构数量多,在空间分布均匀,复杂程度低;而粒径较大的矿物结构数量少,空间分布集中,复杂程度高。模拟结果显示矿物含量越多,空间分布越复杂,煤岩峰值强度越大;当矿物含量接近时,矿物结构空间分布对峰后软化段的影响更大;位于矿物所在的区域出现明显应力集中,且应力集中区域与矿物的分布区域大小相关;对于塑性区域分布的影响,粒径大的矿物结构相比粒径小的更加明显。

In order to study the influence of the geometry,size and distribution of mineral structure on the macroscopic mechanical behavior and deformation and failure characteristics of coal rock,a three-dimensional visualization model of the mineral structure has been established through CT scanning and three-dimensional reconstruction.The characteristics of mineral structures in different equivalent diameters have been analyzed.On this basis,a heterogeneous numerical model with four different equivalent diameter mineral structures has been constructed and subjected to uniaxial compression simulation analysis.The results have shown that the mineral structures with smaller particle size are larger in number,uniform in the spatial distribution,and lower in the complexity.The mineral structures with larger particle size are fewer in number,concentrated in distribution and higher in the complexity.The simulation results have shown that the more the mineral content is,the more complex the spatial distribution is,and the greater the peak strength of coal rock is When the mineral content is similar,the spatial distribution of mineral structure has greater influence on the softening section of stress-strain curve.The obvious stress concentration occurs in the mineral zone,and the stress concentration area is related to the size of the mineral distribution area.As for the influence of the plastic area distribution,the large size mineral structure is more obvious than that of the small size.