Evaluation of Liquefaction Potential According to Resistivity and CPT Data

Abstract

This study investigates the liquefaction potential in Tambak Wedi Subdistrict, Surabaya, employing the electrical resistivity geophysical method with a dipole-dipole configuration and the Cone Penetration Test (CPT). The electrical resistivity method is utilized to acceess the resistivity values of soil layers and to generate a 2D subsurface profile. The CPT method is applied to confirm the soil layer types and to compute the safety factor (SF). The soil data from both methods are subsequently analyzed to evaluate the liquefaction potential based on the soil resistivity and SF values. The analysis incorporates a Peak Ground Acceleration (PGA) of 0.3g and considers an earthquake magnitude of 7.5 Mw. The findings from this study reveal that the soil layers ranging from sandy to organic soil, with dominant silt-sandy and clay-silt layers present up to a depth of 10 meters, and clay-silt and clay layers from 11 to 20 meters. Except in the first 2 meters depth, the calculated SF is less than 0.6, indicating a high liquefaction potential in the region. The assessment of liquefaction potential in this study involved the calculation of N-SPT, Liquefaction Potential Index (LPI), and Liquefaction Severity Index (LSI). These findings underscore the importance of incorporating sitespecific geotechnical evaluations into disaster risk reduction strategies, as they provide critical input for the development of effective mitigation plans aimed at minimizing potential loss of life and economic impact.