Time Histories Finite Element Modelling for Irrigation Canal Stability Analysis under the Effects of Liquefaction in the Sibowi Sigi Regency, Indonesia

Abstract

The Gumbasa irrigation canals are one of the water resource infrastructures damaged by the 7.5 Mw Palu-Donggala Earthquake in 2018. Canal reconstruction was performed to restore the function of the irrigation network, supllying a potential area of 8000 ha. Main canal construction is known to pass through areas with liquefaction vulnerability, and seismic factors also play a role in the stability of construction. This study discusses the stability of construction under the influence of earthquake loads on the Gumbasa irrigation main canal in the Sibowi area, Tanambulava district, Sigi Regency. The irrigation main canals are built in a landfill on a subbase soil with the potential for liquefaction. Numerical simulations were carried out using the finite element method under two conditions, namely static and dynamic conditions on soil parameters obtained from the Standard Penetration Test (N-SPT) data obtained previously. Based on the analysis results, depths of 6.5 m to 9 m have partial potential for liquefaction, with no significant decrease in safety factor (SF). In the static analysis, the SF is 1.65 and 2.13. In the dynamic analysis, the SF is 1.64 and 2.12. The vertical displacement is minimum 0.03 m and maximum 0.10 m.