Development of a 2D modified liquefaction potential index map using geophysical data in Pohang, Korea

초록

Following the 2017 Pohang earthquake in Korea, a liquefaction potential index (LPI) was developed to evaluate the liquefaction risk. The present study aimed to develop and test a modified LPI framework to improve the spatial continuity and accuracy of this index. The modified LPI integrated geophysical data, such as multichannel analysis of surface wave (MASW), electrical resistivity tomography (ERT), and drilling log data, to improve the reliability of liquefaction evaluation. Since liquefaction mostly occurs in sandy soil, the modified LPI uses geophysical data as an indicator to estimate soil type by analyzing data correlations. Further, the modified LPI was derived by integrating the probability of sand generated from the actual soil type into the existing LPI framework. By plotting the LPI on a 2D map, the spatial distribution and risk of the liquefiable zone could be assessed. The actual occurrence of sand boils and the estimations based on the modified LPI showed a tendency to coincide, and the modified LPI was able to accurately predict the possible range of liquefaction, while the existing LPI tends to overestimate the liquefaction range. This suggests that the modified LPI can contribute to preventing liquefaction damage in extended 2D and 3D structures. © NSG 2023.All rights reserved.