基于CT图像的岩土细观REV确定及导热模拟  

Representative elementary volume determination and heat conduction simulation for porous geomaterials based on CT images

作　　者：谢传希 迟平 肖荣 褚召祥 李晓昭 XIE Chuanxi;CHI Ping;XIAO Rong;CHU Zhaoxiang;LI Xiaozhao(Zhejiang Baoshu Construction Group Co.,LTD,Wenzhou Zhejiang 325800,China;Yun Long Lake Laboratory of Deep Underground Science and Engineering,Xuzhou Jiangsu 221116,China;School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou Jiangsu 221116,China)

机构地区：[1]浙江宝树建设集团有限公司,浙江温州325800 [2]深地科学与工程云龙湖实验室,江苏徐州221116 [3]中国矿业大学力学与土木工程学院,江苏徐州221116

出　　处：《矿业科学学报》2025年第2期236-247,共12页Journal of Mining Science and Technology

基　　金：国家自然科学基金(42230704,42107156);徐州市科技计划(KC23383)。

摘　　要：岩土宏观热力学特性受其细观组分和孔隙/颗粒结构影响。基于已有文献开展分析研究,提出一种确定岩土孔隙率表征单元体(Representative Elementary Volume,REV)的分形近似判据:d0≈5λmax,即岩土孔隙率REV为立方体单元,其边长约为研究区内部最大孔隙直径的5倍。基于此,选择砂岩和泡沫混凝土2种不同孔隙率水平的岩土介质进行CT扫描,对孔隙/颗粒结构进行三维重构和表征分析,并以三维重构数字结构为几何模型开展稳态导热有限元模拟。研究结果表明:①岩土孔隙率REV与热导率参数约束下的热导率REV大小基本一致;②相对于砂岩这种天然岩土介质的复杂孔隙结构,泡沫混凝土作为人工岩土材料,其孔隙结构高斯正态分布规律性相对明显;③固流组分热导率数量级的差异性以及岩土孔隙/颗粒结构的复杂性对温度场分布有明显影响,热流发生汇聚、发散和变向,从而引起宏观热导率的变化,增加了该参数研究的复杂性。Macroscopic thermo-physical properties as well as heat and mass transfer processes in porous geomaterials are significantly affected by mesoscopic solid/fluid composition and pore/particle structure.Given that,a fractal approximate criterion was proposed in the framework of continuum mechanics,aiming to determine the size of the porosity-based geotechnical representative elementary volume(REV).The criterion can be described as follow:the edge length of the cubic porosity REV approximately equals to five times of the maximum pore diameter of the targeted geomaterials.Based on this new criterion,two types of porous geomaterials:sandstone and foamed concrete,were selected,and the sample CT scanning experiments were carried out.Accordingly,the 3D pore structures were reconstructed and analyzed using obtained 2D CT images, based on which the finite element simulation of 1D steady-state heat conduction was then conducted. The results indicate that: (1) the porosity REV is approximately the same size as the thermal conductivity REV;(2) the pore structure of artificial foamed concrete is relatively organized than that of natural sandstone;(3) orders of magnitude discrep-ancy in thermal conductivity of solid/ fluid components and complex pore/ particle structure have signifi-cant effect on the temperature distribution during heat conduction, which in turn leads to convergence, divergency and turning of conduction heat flow, finally causing variation of the macroscopic effective thermal conductivity (ETC) and resulting in complexity of related research efforts on the prediction of the ETC of tanglesome geomaterimals.

关 键 词：多孔介质 表征单元体 孔隙率 热导率 分形 

分 类 号：TD411[矿业工程—矿山机电]