Monitoring the risk of large building collapse using persistent scatterer interferometry and GIS

Abstract

In this study, we analyzed the displacement of large buildings in downtown areas. First, we improved an existing Persistent Scatterer InSAR technique and developed an algorithm to calibrate temperature data. Second, we collated TerraSAR-X satellite images of Seoul captured over 22 months from November 2011 to September 2013, automatic weather system data, and a topographic map. Third, the Gangnam Station area, one of the most crowded areas of downtown Seoul, was selected as a study area for precise analysis. We used the algorithm to analyze the displacement rates of downtown buildings. Fourth, by processing GIS data of the study area, we analyzed the individual displacements of 15 large buildings. These buildings occupied the top 0.1 percent of the building area. The average displacement rate of these 15 large buildings caused by vertical land rising and settlement was 4.7 mm. Fifth, three of the 15 large buildings were found to have undergone significant settlement (‘-’ displacement). One of them, CHA Gangnam Medical Center, which is located at one of the exits of Eonju Station. Over the study period, a maximum displacement of -20 mm was observed. In addition, these buildings were located near subway lines and very close to areas where road collapses and underground holes had been reported in the past. These results show that the method used in this study is effective for analyzing the displacement of large buildings in broad downtown areas. Using this method, it will be possible to respond to signs of settlement and collapse of large buildings in advance.