Analysis of liquefaction potential in Opak Fault nearby area (case study: Solo-Yogyakarta-NYIA Kulon Progo Toll Road construction section I.2)

Abstract

Construction of the Solo – Yogyakarta – NYIA Kulon Progo Toll Road Section I.2 is a part of Java's toll road network system that connects Solo and Yogyakarta. The presence of this opak fault allegedly cut the toll road alignment. Based on Indonesia's Liquefaction Vulnerability Zone Map, the alignment location is in a medium liquefaction vulnerability zone. This study aims to determine the potential of liquefaction in the construction of Solo – Yogyakarta – NYIA Kulon Progo Toll Road Section I.2 (stationing 29+000 - 36+000). The maximum peak ground acceleration on the surface was calculated using the Deterministic Seismic Hazard Analysis calculation. Calculating liquefaction potential analysis uses the simplified procedure method developed by Idriss and Boulanger. The research shows that ten borehole points with sandy soil types 2 m – 18 m below the surface have liquefaction potential. The depth of the groundwater table is between 0.2 m – 10 m below the ground surface. Based on the Liquefaction Potential Index analysis, the research location is in a low - high level of liquefaction vulnerability.