Terrestrial LiDAR system accuracy investigation for slow-moving landslide deformation

Abstract

Landslides are a special kind of geological hazard found throughout the entire world. The methods to predict the timing of landsliding and to study its kinematics or consequences are timely topics in research. Terrestrial laser scanning technology has been used for predicting and researching geological hazards for two decades. This research focuses on using terrestrial light detection and ranging (LiDAR) to measure the slow-moving displacement of both the surface and the subsurface soil of landslides and investigating LiDAR system accuracy. Physical modeling was done to simulate the performance of special targets mounted on rods driven into an active landslide, measured using terrestrial LiDAR to improve the scanning accuracy. The primary conclusions from this research are as follows: (1) several tests were done to prove that the terrestrial three-dimensional LiDAR scanner used in this research can precisely obtain the three-dimensional position, displacement, and rotational angle of scanning targets, which can present shallow surface movement of slow-moving landslides. (2) Two kinds of special scanning targets were used for the laser scanner to measure the displacement of surface and subsurface soil in sandbox tests. These consist of spherical Styrofoam targets mounted on rigid metal rods driven into the soil to help the LiDAR scanner improve the accuracy of scanning results and obtain the shallow surface soil movement in the test model. (3) A large-scale field test was designed to prove the feasibility of extending the function of the LiDAR system to obtain the shallow subsurface displacement of landslides and improve the accuracy of the scanning results.