Estimating of Post-liquefaction Settlement Based on SPT Data in Klaten Regency, Central Java

Abstract

A strong earthquake with Mw 6.3 occurred in Yogyakarta on May 27, 2006, causes of damage to DI Yogyakarta Province and Central Java Province, including Klaten Regency. The geological stratigraphy consists of volcanic breccias, lava and tuff in this area and generally shallow groundwater levels, which can trigger liquefaction. The potential liquefaction analysis in this study uses Standard Penetration Test (SPT) data carried out in 3 districts, namely Delanggu, Polanharjo, and Karanganom District uses Idriss-Boulanger method. The peak ground acceleration was calculated by Next Generation Attenuation (NGA) method using data obtained from the Pacific Earthquake Engineering Research (PEER) Center database. The peak ground acceleration that causes liquefaction in this study is at least 0.29 g in bedrock. All areas indicated potential liquefaction with varying depths. Polanharjo District is the most susceptible to potential liquefaction. The method proposed by Zhang estimates post-liquefaction settlement in this study from 3.3 – 42.4 cm (light to extensive damage) in Klaten Regency. Based on the results, further mitigation studies are needed in Klaten Regency to minimize settlement that will occur due to liquefaction. This study is required in planning the construction of toll road in Klaten Regency.