Triaxial test on both saturated and unsaturated soils is associated with non-uniform deformation, especially during shearing. This non-uniform deformation plays an important role in the soil strength and constitutive behavior. In the past, several image-based methods have been proposed to measure non-uniform soil deformation. However, accurate non-uniform soil deformation measurement during triaxial testing is still a great challenge for researchers. This study documented a new technique for the visualization of a deforming specimen during triaxial testing based on a full-field deformation measurement system with help of a self-developed software package GeoTri3D. A dot matrix (i.e., 13,320 dots in 90 rows × 148 columns) at a density of 57 dots/cm² is directly printed to a latex membrane which covers a 61.8 × 123.2 mm specimen during triaxial testing. With the deformation measurement system, three-dimensional (3D) coordinates of each dot on membrane surface are accurately measured at different axial displacements during loading. Point clouds, which represent the specimen surface at these displacement levels, are then generated and further utilized for the generation of triangular meshes and reconstruction of specimen 3D surfaces. The full-field deformations (i.e., axial displacement, radial and axial strain) during testing are then derived based on the triangular meshes. These 3D surfaces and full-field deformations facilitated a 3D visualization of the specimen deforming process at an unprecedented high resolution. Accurate reconstruction of specimen surface and the associated 3D visualization of the deforming process offer a great potential for advanced soil behavior characterization.

饱和土和非饱和土的三轴试验与非均匀变形有关，尤其是在剪切过程中。这种非均匀变形在土壤强度和本构行为中起着重要作用。过去，已经提出了几种基于图像的方法来测量非均匀土壤变形。然而，在三轴试验过程中准确测量非均匀土壤变形仍然是研究人员面临的一大挑战。这项研究记录了一种新技术，用于在三轴测试期间基于全场变形测量系统在自主开发的软件包 GeoTri3D 的帮助下可视化变形试样。密度为 57 点/cm ^{2 的}点阵（即 90 行 × 148 列中的 13,320 个点）在三轴测试期间，直接打印到覆盖 61.8 × 123.2 mm 样品的乳胶膜上。使用变形测量系统，可以在加载过程中在不同的轴向位移下准确测量膜表面每个点的三维 (3D) 坐标。然后生成代表这些位移级别的试样表面的点云，并进一步用于生成三角形网格和重建试样 3D 表面。然后基于三角形网格导出测试期间的全场变形（即轴向位移、径向和轴向应变）。这些 3D 表面和全场变形以前所未有的高分辨率促进了样品变形过程的 3D 可视化。