Analisis Potensi Likuifaksi dengan Data CPT (Cone Penetration Test) Studi Kasus Proyek-X di Surabaya Pusat

Abstract

Liquefaction is the process of changing the nature of the soil from a solid state to a liquid state caused by cyclic loads during an earthquake. Liquidation occurs in non-cohesive soils (silt to sand) that contain many macro pores, so the ability to hold or bind the water is small. In general, liquefaction occurs in earthquakes above 5 Mw and has shallow groundwater conditions. The city of Surabaya has an earthquake potential of 6.5 Mw and has shallow ground water level. This is what underlies the authors to analyze the potential liquefaction in Surabaya. The liquefaction potential is analyzed by utilizing the Youd-Idriss method (1996) and the Cetin method (2004). A case study selected for this study is located at Porject X, Central of Surabaya. The liquefaction analysis was performed by considering four CPT data which have depth of 9m-14.2 m. The liquefaction potential is expressed by the CRR (cyclic resistance ratio) and CSR (cyclic shear ratio), whick will be influenced the factor of safety (FS). If the FS is more than or equal to 1 than the no soil liquefaction is predicted to occur. Differently, soil liquefaction is concluded to occur if FS is less than 1. The Results of Youd-Idriss method (1996) show that the CRR and CSR are about 0.09 to 2.88 and 0.33 to 0.43, respectively. The FS value is about 0.21 to 7.60. Furthermore, CRR and CSR values obtained by using Cetin method (2004) are about 0.04 to 0.06 and 0.22 to 0.36, respectively. The FS value is about 0.15 to 0.23. From the results of the analysis can be concluded that the FS values produced by Cetin (2004) is smaller as compared to Youd-Idriss method (1996)