Aditya Maulana B., A. Asseggaf, Aditya U.

ANALISIS KERENTANAN LIKUIFAKSI BERDSARKAN DATA SPT KECAMATAN KOJA, JAKARTA UTARA

Introduction

Analisis kerentanan likuifaksi berdsarkan data spt kecamatan koja, jakarta utara. Analisis kerentanan likuifaksi akibat gempa di Koja, Jakarta Utara menggunakan data SPT. Temukan potensi likuifaksi rendah hingga sangat tinggi (LPI 1.0-28.68) pada gempa 6-7.5Mw.

Abstract

Abstrak Bencana yang sering terjadi di beberapa wilayah di Indonesia adalah gempabumi. Salah satu akibat dari gempabumi adalah likuifkasi, yaitu fenomena tanah yang kehilangan kekuatan lapisannya karena getaran dan air pada tanah. Peristiwa likuifaksi dapat menimbulkan amblesan, keruntuhan pada bangunan, retakan tanah, kelongsoran, dan lain – lain. Tujuan penelitian ini adalah untuk mengetahui paramaeter yang mempengaruhi kerentanan likuifaksi, mengetahui Faktor Keamanan (FK) berdasarkan perhitungan Cyclic Stress Ratio (CSR) dan Cyclic Resistance Ratio (CRR) menggunakan data SPT, mengetahui tinggi-rendahnya potensi likuifaksi berdasarkan nilai LPI, dan mengetahui kerentanan likuifaksi pada gempa magnitude 5,5 hingga 7,5Mw pada daerah Koja, Jakarta Utara. Pada Penelitian ini menggunakan metode Youd dan Idriss NCEER (1996&1998). Berdasarkan hasil analisis titik uji DB-3 pada mahnitude 5.5 hingga 7,5 Mw dan percepatan maksimum 0,15 didapatkan hasil bahwa daerah Koja tidak aman terhadap likuifaksi dimulai pada gempa magnitude 6 hingga 7,5Mw dengan nilai LPI 1,0 hingga 28,68 atau berpotensi rendah hingga sangat tinggi. Kata-kata kunci: Cyclic Stress Ratio (CSR), Cyclic Resistance Ratio (CRR), FaktorKeamanan (FK), Magnitude, dan Indeks Potensi Likuifaksi (LPI) AbstractDisasters that often occur in several regions in Indonesia are earthquakes. One of the consequences of earthquakes is liquefaction, which is a soil phenomenon that loses the strength of the layer due to vibration and water to the soil. Liquefaction events can cause subsidence, collapse in buildings, soil cracks, landslides, etc. The purpose of this study was to knows the parameters that affect liquefaction vulnerability, knows Safety Factors (FS) based on calculation of Cyclic Stress Ratio (CSR) and Cyclic Resistance Ratio (CRR) used SPT data,knows the high-low potential for liquefaction based on LPI value, and knows vulnerability liquefaction on earthquake magnitude 5.5 to 7,5Mw in Koja, North. This study usedthe Youd and Idriss NCEER methods (1996,1998). Based on analysis on DB-3 on magnitude 5,5 hingga 7,5 Mw and maximum acceleration of 0.15, the result was Koja had potential for liquefaction with magnitude earthquake started at 6 to 7,5 Mw with LPI value 1,0 to 28,68 or low potential to very high potential.Keywords: Cyclic Stress Ratio (CSR), Cyclic Resistance Ratio (CRR), Safety Factor (FK), Magnitude, and LiquefactionPotential Index (LPI)

Review

This paper presents a timely and relevant analysis of liquefaction vulnerability in Koja District, North Jakarta, a region prone to seismic activity in Indonesia. Recognizing the severe consequences of earthquake-induced liquefaction, such as subsidence and structural collapse, the study aims to assess the susceptibility of local soils. Utilizing Standard Penetration Test (SPT) data, the research methodically investigates the parameters influencing liquefaction potential, specifically focusing on understanding the safety factors and overall vulnerability across a range of earthquake magnitudes. The objective to provide a localized risk assessment for Koja District underscores the practical importance of this work for urban planning and disaster mitigation efforts. The methodology employed in this study follows the established Youd and Idriss NCEER (1996 & 1998) methods, which are widely accepted for liquefaction assessment. The authors calculated the Factor of Safety (FS) based on Cyclic Stress Ratio (CSR) and Cyclic Resistance Ratio (CRR), subsequently determining the Liquefaction Potential Index (LPI). A key finding, derived from analysis at test point DB-3 with a maximum acceleration of 0.15g, indicates that Koja District is indeed susceptible to liquefaction. Specifically, the area is deemed unsafe for earthquakes ranging from Magnitude (Mw) 6.0 to 7.5, with LPI values varying significantly from 1.0 to 28.68. This wide range suggests that the potential for liquefaction in Koja can span from low to very high, depending on the specific earthquake magnitude and local soil conditions. While the study provides critical initial insights into liquefaction vulnerability in Koja, its scope, as presented in the abstract, appears limited to a single test point (DB-3) for the detailed results. A more comprehensive assessment would ideally incorporate data from multiple boreholes to provide a spatially representative understanding of the entire district's vulnerability. Nevertheless, the findings highlight a significant seismic risk for North Jakarta and serve as a crucial alert for urban planners and civil engineers. Future research could expand upon this foundation by integrating more extensive geotechnical data, developing detailed hazard maps for the entire district, and exploring the implications of these findings for specific infrastructure designs and land-use regulations within Koja.

Full Text

Comments

You need to be logged in to post a comment.