STUDY OF LIQUEFACTION POTENTIAL IN TOLL ROAD CONSTRUCTION ON FINE-GRAINED SOIL

Liquefaction is a natural phenomenon indicating the transformation of soil into a liquid state. This condition occurs when saturated sandy soil experiences shaking, causing an increase in pore water pressure and decreasing effective soil stress. This study aims to assess the liquefaction potential in the Solo-Yogyakarta-NYIA Kulonprogo Toll Road. Although several parameters influence the potential of liquefaction, this toll road must be vigilant due to its proximity to seismic sources. Preparing for liquefaction potential is crucial to ensure the stability of structures throughout their service life. This research thoroughly investigated liquefaction potential from the identification to the evaluation stage of 21 boreholes that indicate highly fine-grained soils. The identification stage was conducted through grain size and soil properties analysis. The evaluation stage used the Factor of Safety (FS) with the Simplified Procedure and the Liquefaction Potential Index (LPI). The identification results show that several boreholes have liquefaction grain gradations and soil properties. The evaluation results using Peak Ground Acceleration (PGA) by Kanno Attenuation resulted in three borehole locations with FS < 1. The classification of liquefaction potential in these three boreholes is high and low. The analysis shows that one of the three boreholes has a significantly higher fines content than the others. Further investigation of this uniqueness can be conducted using another method, such as numerical analysis.