Topography is a crucial characteristic reflecting the stability status of a landslide dam. The methods for measuring landslide dam topography in a laboratory-scale test study are currently operator dependent, time-consuming, or only applicable to the measurement of the two-dimensional section. In this paper, a laboratory-scale photogrammetric method based on the structure from motion (SfM) technique was proposed to measure the three-dimensional (3D) topography of a landslide dam. The SfM technique, which is a revolutionary, low-cost, user-friendly computer vision technique, was employed for reconstructing a landslide dam 3D computer model. A scientific method to determine the topography parameters of a landslide dam was put forward. Meanwhile, two materials with different particle sizes were used to simulate the formation process of the landslide dam in the laboratory-scale. Then, the measurement results of the two materials were compared. Five parameters of a landslide dam topography with 100 parallel measurement results for each parameter were obtained. The results show that the SfM technique could build a high-quality 3D point cloud in a laboratory scale. The proposed method of determining the topography parameters of a landslide dam was useful and has low measurement uncertainty. The material type affected the sparse density of the point cloud and then affected the measurement uncertainty of landslide dam topography parameters. The measurement uncertainty of the gravel-type landslide dam was significantly higher than that of the sand-type landslide dam. This research contributes to promoting the application of a photogrammetric method based on the SfM technique in geotechnical engineering laboratory-scale tests.

地形是反映滑坡坝稳定状态的关键特征。目前，在实验室规模的试验研究中，滑坡坝地形的测量方法依赖于操作员，耗时或仅适用于二维截面的测量。本文提出了一种基于运动结构（SfM）技术的实验室规模摄影测量方法，用于测量滑坡大坝的三维（3D）地形。SfM技术是一种革命性，低成本，用户友好的计算机视觉技术，被用于重建滑坡坝3D计算机模型。提出了确定滑坡坝地形参数的科学方法。与此同时，在实验室范围内，使用两种具有不同粒径的材料来模拟滑坡坝的形成过程。然后，比较两种材料的测量结果。获得了滑坡坝地形的五个参数，每个参数具有100个平行测量结果。结果表明，SfM技术可以在实验室规模上构建高质量的3D点云。所提出的确定滑坡坝地形参数的方法是有用的，并且测量不确定度低。物质类型影响点云的稀疏密度，然后影响滑坡坝地形参数的测量不确定性。砾石型滑坡坝的测量不确定度明显高于砂型滑坡坝。