Perpustakaan Digital ITB

Ground failures generated by liquefaction had been a major cause of damages in Indonesia during past earthquakes among others: 2006 Yogyakarta, 2009 Padang, and 2018 Palu earthquake. Estimating deformations due to seismically induced liquefaction is often accomplished with a series of simplified analyses. An alternative approach adopting coupled effective stress analysis is presented in this paper to estimate liquefaction-induced flow failure in the effort to provide improvement in the deformations prediction. The method is adopted for the liquefaction slope occurrence during 2018 Palu earthquake. In order to assess the liquefaction potential and analyze the seismic deformation response of the slope, subsurface exploration has been carried out in several liquefied sites. The Palu liquefaction occurrence was also identified to be contributed by aquifer existence beneath the liquefied layer. This liquefaction of the sand layers in combination with the aquifer pressure under high seismic excitation contributes to the flow liquefaction that travel long distance which has damaged many houses along the critical zones in Petobo, Jono Oge, and Balaroa. Numerical analyses adopting effective stress method coupled with the aquifer pressure were carried out to verify the liquefaction occurrence. An effective stress dynamic analyses were carried out using FLAC2D version 7.0 (Itasca, 2011) utilizing UBCSAND constitutive model. Additionally, the large-strain mode is applied to calculate liquefaction-induced flow failure. The proposed approach can be used both for post-earthquake evaluations and for pre-earthquake vulnerability predictions on others area.