As-built verification and condition assessment of Mechanically Stabilized Earth (MSE) and Geosynthetic-Reinforced Soil (GRS) Retaining Structures using 3D Point Cloud Data
Department: Civil and Environmental Engineering
Advisor: Michael McGuire
Remote sensing technologies, such as lidar and photogrammetry, have significant potential for condition assessment, as-built verification, and forensic investigation of earth retaining structures. While these technologies have previously been used to survey large scale areas for topographic mapping and management of assets such as bridges and roads, this research utilizes the high accuracy of modern remote sensing for analyzing mechanically-stabilized earth (MSE) and geosynthetic-reinforced soil (GRS) retaining structures on a smaller scale. As part of this research, a method was developed to analyze three-dimensional survey measurements obtained using lidar and photogrammetry to measure the position and displacement of the wall facing materials of these structures. This information is used to characterize the condition of the structure and infer the causes of observed distress to the wall face. When applying the method, the facing is characterized using vertical profiles along the length of the wall. Profiles developed using survey data obtained at one time can be used to assess the current condition of the wall including vertical and horizontal alignment. Profiles developed using data from surveys conducted at different times can be used to observe the displacement of the facing over the time period between the surveys. This capability is helpful for long term performance monitoring of the structure. This analysis methodology was developed using a combination of small-scale laboratory experiments and full-scale field applications. Lab results were compared to known displacement values to ensure the accuracy of the analysis while field data was used to ensure the analysis could be applied to actual structures. The analysis process will be refined and developed into an automated program to reduce the amount of work necessary and enable more widespread application. Along with the analysis program, recommendations will be developed outlining field procedures and the suitability of specific technologies for each application.
About Michael Yust:
Michael Yust is a senior at Lafayette College in Civil and Environmental Engineering. Since Fall 2014 he has been working with Professor McGuire studying applications of remote sensing in geotechnical engineering, specifically earth retaining structures. He has presented his research at the 2015 Central PA Geotechnical Conference and the 2016 Geotechnical and Structural Engineering Congress. Upon graduation Michael plans to pursue graduate studies in geotechnical engineering.