This study investigates soil liquefaction potential, specifically focusing on fine-grained soils. We analyze the soil behavior index (Ic) values, emphasizing their role in distinguishing between soils susceptible and resistant to liquefaction. Multiple Ic formulas from the existing literature undergo rigorous examination and refinement to improve accuracy in differentiating soil types. Data from Adapazarı, Türkiye, post-1999 earthquake, and cone penetration test (CPT) results from an acoustic CPTU machine inform the study. Various scenarios, considering 11 literatures from physical properties of the soil, evaluate the potential for liquefaction. The threshold Ic values that best distinguish liquefied and non-liquefied fine-grained soils from each other are determined. Performance assessment identifies the most suitable approach for accurate discrimination. To enhance the chosen scenario, an optimization process determines the optimal coefficients for different Ic formulas. With these optimized Ic formulas, liquefied and non-liquefied soils are analyzed again and the most appropriate threshold values are found. The results show improved accuracy in assessing the liquefaction potential. This study significantly advances liquefaction analysis techniques, introducing novel recommendations, refining criteria, optimizing Ic formulas, and offering insights into nonliquefiable soil classification based on CPT data. The findings aim to improve the safety and effectiveness of geotechnical engineering practices, particularly during seismic events.