Assessment of post-liquefaction potential in soil displacement on irrigation canal reconstruction project in the Jono Oge and Lolu area, Central Sulawesi, Indonesia

¹ Department of Civil and Environment Engineering, Faculty of Engineering, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
² Directorate General of Construction Development, The Ministry of Public Works and Housing, South Jakarta 12110, Indonesia

^* Corresponding author: sito.ismanti@ugm.ac.id

Abstract

A seismic event of magnitude 7.5 Mw took place in Central Sulawesi in September 2018, marking a significant occurrence in the geological hazard chronicles of Indonesia. The occurrence of liquefaction subsequent to the earthquake significantly damaged the water resource infrastructure in the Sigi Regency. This study aims to evaluate the possible soil displacement resulting from re-liquefaction events occurring in the main irrigation canals in the Jono Oge and Lolu regions. The study used semi-empirical and finite element analysis to compute the lateral displacement index and reconsolidation settlement within the designated study region. The examination of soil displacement is conducted under various groundwater level scenarios, utilizing the most recent soil investigation conducted in 2021. The findings of the study indicate that raising the groundwater level to -3.5 meters will result in significant soil and irrigation canal damage. In the future, it is suggested that limiting the groundwater level below -11 meters in the primary irrigation canal area might effectively mitigate soil lateral displacement and settlement.