ANALISIS POTENSI LIKUIFAKSI DI KALI OPAK IMOGIRI DAERAH ISTIMEWA YOGYAKARTA (STUDI EKSPERIMENTAL DAN ANALISIS EMPIRIS)

• Main Authors: , LINDUNG ZALBUIN MASE, , Teuku Faisal Fathani, ST., MT., Ph.D.
• Format: Theses and Dissertations NonPeerReviewed
• Published: [Yogyakarta] : Universitas Gadjah Mada 2013
• Subjects: ETD
• Online Access: https://repository.ugm.ac.id/122926/; http://etd.ugm.ac.id/index.php?mod=penelitian_detail&sub=PenelitianDetail&act=view&typ=html&buku_id=63035
• Institution: Universitas Gadjah Mada

Liquefaction is a disaster which may cause extensive damages. To minimize the liquefaction risk, an experimental study and empirical analysis to understand the potential of liquefaction that may happen should be conducted. A liquefaction experimental study using shaking table and grain size analysis was performed to study liquefaction. Sand from Opak River, Imogiri, Yogyakarta was used in this study. The liquefaction potential analysis was conducted by taking into account several parameters i.e. earthquake maximum ground acceleration of 0.3 to 0.4 g, vibrational frequency of 1.4 to 1.8 Hz, vibration time of 8,16, and 32 second, and variation of pore water pressure reading (headmeter, manometer, dan pressure traducer). The empirical analysis of liquefaction potential was performed using maximum stress method of rigid soil column combined with grain size data and using N-SPT data. Based on the result of grain size testing, the sand from Opak River, Imogiri, Yogyakarta is classified as the sand which is most vulnerable to liquefaction. The evaluation graph of liquefaction potential based on grain size is obtained with cyclic load variation. The graph is getting more flattened as the cyclic load is getting bigger. The ratio of shear stress and total vertical stress (�h/�v) of each relative density decreases as the cyclic load increases. The result of analysis using shaking table shows that Opak River sand has liquefaction potential for every dynamic load given. The ratio of maximum excess pore water pressure is 2,4 (headmeter), 1,28 (manometer), dan 1,07 (pressure tranducer). As the maximum ground acceleration is bigger, the maximum excess pore water pressure ratio is also bigger. Larger maximum acceleration in a frequency results in relatively longer liquefaction duration. The maximum liquefaction duration is 110 second (headmeter), 33 second (manometer), and 37 second (pressure tranducer). The longer the vibrational time, the bigger the maximum excess pore water pressure ratio. The bigger the vibrational frequency, the bigger excess pore water pressure ratio. The result of N-SPT data analysis shows that Opak River Imogiri sand has liquefaction potential from 6 to 20 meter deep.