Studi Pengaruh Likuifaksi Tanah terhadap Perilaku Daya Dukung Pondasi Tiang dalam Menerima Beban Vertikal

Suhardji, Taurina (2025) Studi Pengaruh Likuifaksi Tanah terhadap Perilaku Daya Dukung Pondasi Tiang dalam Menerima Beban Vertikal. Masters thesis, Institut Teknologi Sepuluh Nopember.

Text 6012231047-Master_Thesis.pdf - Accepted Version Restricted to Repository staff only Download (11MB) | Request a copy

Abstract

Likuifaksi merupakan fenomena geoteknik dimana tanah kehilangan kekuatan akibat peningkatan tegangan air pori di bawah kondisi undrained dan pembebanan dinamis. Penelitian ini menggunakan metode empiris dan software FEM MIDAS FEA NX untuk menganalisis daya dukung pondasi tiang. Pemodelan pada software menggunakan 1D untuk beam sebagai pondasi tiang, dan 2D plane strain untuk model tanah. Karakteristik percepatan gempa diperhitungkan serupa dengan lokasi yang ditinjau, yaitu Badung, Bali. Area yang ditinjau terbagi menjadi Zona A dan Zona B, dengan jenis lapisan heterogen dan homogen. Diameter pondasi tiang yang digunakan adalah 0.40 m, 0.60 m, dan 0.80 m dengan variasi bentuk penampang yaitu persegi dan lingkaran. Analisis daya dukung pondasi menunjukkan penurunan akibat likuifaksi, baik menggunakan metode empiris maupun FEM. Pada metode empiris, hanya diperoleh daya dukung selimut pada lapisan likuifaksi menurun hingga 100%. Sedangkan jika menggunakan FEM, mobilized shear force menurun hingga 19 – 26% pada Zona A secara umum di akhir tahap likuifaksi, dan 50 – 90% pada Zona B. Berdasarkan asumsi lapisan tanah berupa heterogen dan homogen, perbedaan daya dukung ultimit termobilisasi tidak jauh berbeda, yaitu berada pada rentang 1 – 4%. Berdasarkan bentuk penampang, bentuk persegi memiliki mobilized shear force berada pada rentang 30 – 70%, sedangkan penampang lingkaran yang mengalami penurunan pada rentang 50 – 80%. Sedangkan berdasarkan analisis antar-diameter, penurunan mobilized shear force memiliki perbedaan nilai 10% seiring dengan mengecilnya diameter pondasi.

================================================================================================================================================================================================================================================
Liquefaction is a geotechnical phenomenon in which soil loses its strength due to increased pore water pressure under undrained conditions and dynamic loading. This study employs both empirical methods and the finite element method (FEM) using MIDAS FEA NX software to analyze the bearing capacity of pile foundations. The modeling in the software applies 1D beam elements to represent the piles and 2D plane strain elements for the soil. Seismic acceleration characteristics are considered in accordance with the site conditions in Badung, Bali. The study area is divided into Zone A and Zone B, representing heterogeneous and homogeneous soil layers, respectively. The diameters of the analyzed piles are 0.40 m, 0.60 m, and 0.80 m, with cross-sectional shapes consisting of square and circular forms. The analysis of pile bearing capacity shows a reduction due to liquefaction, both in empirical and FEM-based approaches. In the empirical method, the analysis considers only the reduction of skin friction along the pile shaft within liquefied layers, which may decrease by up to 100%. Meanwhile, in the FEM approach, the mobilized shear force decreases by approximately 19–26% in Zone A at the final stage of liquefaction, and 50–90% in Zone B. When comparing heterogeneous and homogeneous soil assumptions, the difference in mobilized ultimate bearing capacity is relatively small, ranging from 1% to 4%. In terms of cross-sectional shape, square piles exhibit a mobilized shear force reduction ranging from 30% to 70%, whereas circular piles experience a reduction of 50% to 80%. Regarding pile diameter, the reduction in mobilized shear force varies by around 10%, with smaller diameters resulting in greater reductions.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Daya Dukung, Gempa, Likuifaksi, Pondasi Tiang, Bearing Capacity, Earthquake, Liquefaction, Pile Foundations
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA775 Foundations.
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Civil Engineering > 22101-(S2) Master Thesis
Depositing User:	Taurina Suhardji
Date Deposited:	04 Aug 2025 09:45
Last Modified:	04 Aug 2025 09:45
URI:	http://repository.its.ac.id/id/eprint/125978

Actions (login required)

View Item