Analysis of Liquefaction Potential in Solo-Yogyakarta-NYIA Kulon Progo Sta. 16+700 – 22+500

Abstract

The Solo-Yogyakarta-NYIA Kulon Progo is a National Strategic Project to accelerate the accessibility to New Yogyakarta International Airport (NYIA). This toll road will pass through Central Java Province and the Special Region of Yogyakarta Province. Previous studies have investigated that during the 2006 Yogyakarta Earthquake with a moment magnitude, Mw of 6.3, liquefaction was found in some areas in Klaten Regency of Central Java Province. This study aims to determine liquefaction potential in the Solo-Yogyakarta-NYIA Kulon Progo Toll Road Section 1, focusing on stations 16+700 to 22+500, which were located in Klaten Regency. This study first analyzes soil conditions and groundwater depth based on soil investigation data. Analysis of liquefaction potential was found out using Idriss-Boulanger based on Standard Penetration. Parameter of peak ground acceleration using two approaches; probabilistic and deterministic. For probabilistic, the peak ground acceleration using probability of 7% in 75 years and 2% in 50 years. For deterministic using the attenuation function of Campbell and Bozorgnia (2014). Then, the Liquefaction Potential Index was also used to determine the level of liquefaction vulnerability in the study area. The results of liquefaction potential analysis using each approach of peak ground acceleration show the differences in safety factor of liquefaction values. It can be concluded that several sites along the study area have the potential to liquefy at a very low to a very high level, with PGA value at least 0,43 for probability of 2% in 50 years, 0,32 for probability of 7% in 75 years, and 0,36 for deterministic approaches sourced by Opak Fault. Then, the location with the highest liquefaction potential is at stationing 20+550, with LPI values of each approach of 42.91, 33.36, and 34.70.