Displacement Estimation Performance of a Cost-Effective 2D-LiDAR-Based Retaining Wall Displacement Monitoring System

Monitoring the displacement of retaining walls is essential for maintaining their stability. Traditional displacement monitoring by inclinometer is costly and time-consuming, owing to the need for manual measurements. A recently developed 2D-LiDAR-based retaining wall displacement monitoring system offers advantages over traditional methods, such as easy installation and dismantling, as well as the cost-effective monitoring of three-dimensional displacement compared to terrestrial laser scanners (TLSs). However, a previous study did not account for the actual deformation of the retaining wall, potentially compromising the reliability of the displacement estimation. This study aims to assess the displacement estimation performance of the system by using a retaining wall that simulates real-world deformations, considering key parameters related to the displacement estimation algorithm and the quality of point cloud data. Using the multiple model-to-model cloud comparison algorithm and a developed algorithm for filtering duplicate point cloud data, the system’s average performance across various deformation types yielded mean absolute error (MAE), MAEDmax, and compound error values of 1.7, 2.2, and 2.0 mm, respectively. The results demonstrate that even a 2D-LiDAR, which has lower precision than a TLS, can effectively monitor retaining wall displacement through the post-processing of point cloud data.