基于CT扫描的土石混合体三维数值网格的建立

根据CT扫描得到土石混合体切面图像信息，通过二值化和砾石边界识别技术提取砾石表面点云数据，应用逆向工程软件重构砾石的三维模型。编写APDL代码，在ANSYS中快速生成土石混合体的几何模型，借助ANSYS ICEM CFD强大、灵活的网格划分功能，对砾-土界面处网格进行加密，得到土石混合体的三维数值网格，采用接口程序，将数值网格导入FLAC3D中进行模拟计算。通过与无砾石模型计算结果的对比，说明了建立表征土石混合体结构特征的精细三维数值网格可以更加准确地描述土体，特别是砾-土界面的受力情况和变形特征，从而提高土石混合体数值模拟的精确度及可靠度。

3D mesh generation for soil-rock mixture based on CT scanning

Sections of the image information of soil-rock mixture are obtained by CT scanning, the point cloud data of gravel surface are extracted by technology of image binarization and boundary recognition. By using Geomagic Studio, a reverse engineering software, three-dimensional geometric model of the gravel is reconstructed and the geometric model of gravels of the soil-rock mixture imported to ANSYS is quickly obtained. With the features of powerful and flexible function of mesh dividing, ANSYS ICEM CFD is adopted to mesh and generate orderly tetrahedral elements to obtain 3D numerical model of the soil-rock mixture. The gridding along the boundary of the soil and the gravels is densified. By using the interface code, 3D numerical model is imported into FLAC3D for numerical simulation. Comparison with the results of nongravel model, it is shown that the established fine 3D model can reflect the structure characteristic of the soil-rock mixture. Especially, it can precisely describe the stress and the deformation of the soil, as well as the boundary behavior of soil and gravel. The method presented can reduce the error caused by model simplification and improve the accuracy and reliability of numerical simulation.