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土体的细观孔隙结构非常复杂,且对其渗流特性有着重要的影响.为了研究土体的细观孔隙特征及流体在土体孔隙内流动的详细信息,基于土体CT扫描的切片图像,采用数字图像处理技术提取出土体的孔隙率及孔隙的两点自相关函数.根据孔隙率随机生成了土体的细观孔隙结构,然后将土体孔隙的两点自相关函数作为目标函数,采用模拟退火算法对重构土体的细观孔隙结构进行优化运算,从而得到了与真实土体孔隙结构特征相似的细观模型.最后,联合用于多孔介质细观渗流数值模拟的格子Boltzmann方法,对重构土体模型进行了渗流场的数值计算,计算结果表明:土体在渗流过程中主要沿着孔隙连通性较好的通道进行,在局部封闭的孔隙内渗流流速较小,且最大渗流流速通常发生在整体贯通通道的较窄部位.
The mesoscale pore structure of soil is very complicated and has an important influence on its seepage characteristics.In order to study the mesoporosity characteristics of soil and the flow of fluid in the soil pores, based on the slice images of soil CT scanning, The two-point autocorrelation function of porosity and porosity was extracted by digital image processing technique, and the mesostructure of the soil was randomly generated according to the porosity, and then the two-point autocorrelation function of the soil pore was taken as the objective function. Simulated annealing algorithm is used to optimize the mesoscopic pore structure of reconstructed soils, and a mesoscopic model similar to that of the real soil is obtained.Finally, the lattice Boltzmann method, which is used to simulate the mesoscopic seepage of porous media, The numerical simulation of the seepage field is carried out on the reconstructed soil model. The calculation results show that the soil is mainly along the channel with better pore connectivity during the seepage process, and the seepage flow velocity in the partially closed pore is smaller and the maximum seepage The flow rate usually occurs at the narrower part of the entire through passage.