ESTABLISHING METHOD OF 3D GEOLOGICAL MODELS BASED ON AIRBORNE LIDAR DATA AND BIM TECHNOLOGY

摘要

BIM (Building information model) technology has played a significant role in infrastructure engineering design in recent years. The common 2D topographic map measured by digital mapping cannot satisfy the requirement of BIM 3D design. Therefore, the main objective of this study is to establish 3D geological models for BIM 3D design based on Airborne LiDAR data and geophysical data. ALS (Airborne Laser Scanners) is one of the most effective and reliable means of terrain data collection, using LiDAR data for DTM (Digital Terrain Model) generation is becoming a standard practice in spatial related areas. However, original ALS point cloud cannot be used directly due to the low elevation precision and the influence of non-ground data, while this method is more effective in filtering LiDAR ground point cloud, retaining continuous undulate topography at the same time, and obtaining high precision DTM and 3D geological models through 3D point cloud and geophysical data. Firstly, selecting CSF (Cloth Simulation Filtering) algorithm which constructs virtual grid to simulate terrain surface and filter the residual highway and bridge point cloud by RGB features. Next, by fitting the quadric surface by the RTK (Real-Time Kinematic) control points and using the quadric surface equation to correct the elevation value of point cloud, the high precision DTM can be obtained via revised point cloud data. Then. 3D geological models can be established by geophysical data and DTM. The experimental results show that the 3D geological models generated basing on ALS data and geophysical data can satisfy the requirement of BIM 3D design.