Review of a prediction formula for liquefaction-induced building settlements of Taiwan shallow founded buildings - a case study of 2018/02/06 Hualien earthquake event

Abstract

This study aims to use the actual cases of liquefaction-induced building settlements during the Hualien earthquake on February 6, 2018, to examine the empirical prediction formula for liquefaction-induced building settlements developed in Taiwan for liquefaction risk assessment. The empirical prediction formula is established by collecting actual cases of liquefaction-induced building settlements during the 1999 Chi-Chi Earthquake and the 2016 Kaohsiung Meinong Earthquake events, and using various indicators obtained from the site liquefaction assessment for statistical regression. This study first reviewed the relevant literature to obtain the analysis information such as basic data of buildings affected by soil liquefaction in the Hualien City, the scope of liquefaction-induced settlements, and representative geological boreholes in the liquefaction area. Second, to use the SPT-N based simplified soil liquefaction evaluation methods to calculate the relevant indicators of soil liquefaction potential such as liquefaction potential index P_L, post-liquefaction ground settlements S_L of free field sites, and thickness of the surface non-liquefaction layer. The liquefaction indicators and basic parameters of shallow-founded buildings such as the number of floors and the width of buildings were input to the empirical prediction formula for liquefaction-induced building settlements to estimate the empirical values of liquefaction-induced building settlements. Finally, the estimations would be compared with the actual settlements of shallow-founded buildings during the 2018/02/06 Hualien earthquake to understand the applicability of the empirical prediction formula for the soil liquefaction risk assessment in the Hualien City area. The research results show that the calculated empirical values of liquefaction-induced building settlements are similar to the actual values of settlements, which implies soil liquefaction impacts significantly on the shallow-founded buildings in the Hualien city during 2018/02/06 Hualien earthquake. This empirical prediction formula for Taiwan liquefaction-induced building settlements could be preliminarily applied to the risk assessment of soil liquefaction in the Hualien City area.