A Comparison Method for 3D Laser Point Clouds in Displacement Change Detection for Arch Dams

Dam deformation monitoring can directly identify the safe operation state of a dam in advance, which plays an important role safety management. Three-dimensional (3D) terrestrial laser scanning technology is widely used field due to its fast, complete, and high-density 3D data acquisition capabilities. However, point clouds are characterized by rough surfaces, discrete distributions, affect accuracy analysis two states data. In addition, it impossible extract correspondence points from irregularly distributed cloud unify coordinates states’ data, lines planes often difficult obtain natural environment. To solve above problems, this paper studies displacement change detection method for arch dams based on two-step registration contour model comparison method. environment around dam, stable rock as element improve accuracy, fine using iterative closest algorithm present describe coordinate unification without control network target. Then, analyze variation surface comparing surfaces being affected roughness cloud, fitting compare distance between models. Finally, applied Xiahuikeng Arch Dam, changes entire different periods visualized with existing methods. The results show that middle area generally greater than banks, increasing increase elevation, consistent behavior during reach millimeter-level accuracy.