关键词: 滑坡, 模型试验, 三维激光扫描, 变形监测

Abstract: At present, the deformation analysis in the large-scale landslide physical model tests is mainly carried out with point based measurements which are generally more accurate and precise than area based techniques, especially when control targets are used. However, point based measurements provide only information of a few selected monitoring points and not on the whole surface of the model. 3D laser scanning technology captures the integrated, comprehensive, consecutive and associated panoramic coordinate data with a high degree of precision and resolution in extreme speed. It also describes factually the frame and configuration of the object. 3D laser scanning technology has been successfully applied to displacement monitoring and deformation measurement in the large-scale landslide physical model tests. In order to assess the effectiveness of the measurement methods applied to measure displacement in the laser scanning and evaluate their performances, a validation simulation experiment has been carried out. The error evaluation model of the point positional accuracy is derived. The point density in laser scanning is analyzed theoretically; and a practical test stabilized with model piles has been carried out to better understand the mechanics of such type of landslides. The displacement and deformation obtained by cloud to cloud comparison method, the barycenter method and scan data collection at two different epochs are reasoned to describe synthetically the deformation evolution process of the model here. Researches show that: the error evaluation model and point density model provide a theoretical basis for the evaluation of measurement achievement and the optimal designs for the measurement scheme. The cloud to cloud comparison method and scanning data collection techniques are area based measurements, while barycenter method and the benchmark method are point based. With point based measurement small deformations can be detected in only a few selected positions due to the largely manual measurement process. The area based methods give a good approximation of the displacement amplitudes and provide the whole deformation of the slope surface. The application of the 3D laser scanning technology to the landslide model test has the advantage of combining both the point based and area based methods. It provides the whole deformation while maintaining the high precision for the selected positions.

Key words: landslide, physical model test, 3D laser scanning technology, deformation monitoring