Perencanaan Breakwater di Lamongan Shorebase

Wijaya, Bima Ardyan (2025) Perencanaan Breakwater di Lamongan Shorebase. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Lamongan Shorebase merupakan kawasan pelabuhan strategis di pesisir utara Jawa
Timur yang dikembangkan dalam proyek Eastport Project Phase 1(EPP1). Pada perencanaan
ulang breakwater sepanjang 1774 meter, digunakan kombinasi material geotextile tube sebagai
inti dan batu sebagai lapisan pelindung. Berdasarkan hasil analisis hindcasting data angin tahun
2014-2023 menunjukkan arah dominan dari Barat Laut. Dengan pendekatan Fisher Tippet Type
I dan umur rencana struktur 50 tahun, diperoleh tinggi gelombang rencana H0 = 2,8 meter dan
periode gelombang T0 =9,03 detik. Berdasarkan data pasang surut, nilai MSL adalah 1,07 meter
dan HWS 1,95 meter, sehingga elevasi puncak breakwater direncanakan sebesar 6,89 meter
dengan kemiringan lereng 1:1,5. Struktur breakwater terdiri dari tiga lapisan: pelindung I,
pelindung II, dan inti. Berat batu utama (W) sebesar 5,96 ton, pelindung II sebesar W/10 (0,596
ton), dan inti W/200 (0,030 ton). Lebar puncak 5 meter, ketebalan lapisan pelindung 3 meter,
pada lapisan kedua 1,4 meter. Geotextile tube yang digunakan sebagai inti memiliki tinggi hG
= 1,4 meter dan lebar IG = 4,5 meter.
Dari perhitungan awal tanpa perbaikan tanah, penurunan konsolidasi diperkirakan 7
meter. Untuk mengurangi risiko deformasi, digunakan metode Prefabricated Vertical Drain
(PVD) dengan pola segitiga dan jarak antar drain 1 meter. Berdasarkan hasil perhitungan, tinggi
timbunan pelaksanaan direncanakan sebesar 33 meter, dengan penambahan bertahap sebesar
0,5 m/minggu selama 66 minggu. Analisis waktu konsolidasi menunjukkan bahwa 90% derajat
konsolidasi tercapai dalam 6,75 bulan. Dan direncanakan selimut drainase setebal 1,5 meter
berfungsi sebagai saluran horizontal untuk mengalirkan air yang dikeluarkan oleh
Prefabricated Vertical Drain (PVD).
Analisis stabilitas menggunakan geostudio menunjukkan bahwa penggunaan geotextile
tube dengan 1 lapis memberikan hasil paling efektif dengan nilai SF sebesar 1,662. Analisis
manual dengan metode irisan menghasilkan SF 1,3, stabilitas geser 3,44 > 1,5, dan stabilitas
guling 4,95 > 2, menunjukkan bahwa desain breakwater dengan geotextile tube sebagai inti dan
batu sebagai pelindung memberikan solusi yang efisien dan stabil.
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Lamongan Shorebase is a strategic port area located on the the northern coast of Eas
Java, developed as part of the Eastport Project Phase 1 (EPP1). In the redesign of the 1774
meter long breakwater, a combination of geotextile tube as the core and rock as the protective
layer is used. Based on hindcasting analysis of wind data from 2014 to 2023, the dominant wind
direction is from the North West. Using the Fisher Tippett Type I approaxh and a structural
design life 50 years, the calculated design wave height is H0 = 2,8 meters and the wave period
is T0 = 9,03 seconds. According to tidal data, the Mean Sea Level (MSL) is 1,07 meters and the
Highest Water Spring (HWS) is 1,95 meters, resulting in a planned breakwater crest elevation
of 6,89 meters with a slope of 1 : 1,5. The breakwater structure consists of three layers : primary
armor, secondary armor, and core. The main rock weight (W) is 5,96 tons, the secondary layer
is W/10 (0,596 tons), and the core is W/200 (0,030 tons).The crest width is 5 meters, with
protective layer thicknesses of 3 meters for the outer layer and 1,4 meters for the second layer.
The geotextile tube used as the core has a height of1,4 meters and a width of 4,5 meters.
Based on initial calculations without soil improvement, the estimated consolidation
settlement is 7 meters. To reduce the risk of deformation, the Prefabricated Vertical Drain
(PVD) method was applied in a triagular pattern with 1 meter spacing between drains. Based
on the calculations, the construction embankment height is planned at 33 meters, built in stages
at 0,5 meters per week for 66 weeks. Consolidation time analysis shows that 90% degree of
consolidation is achieved within 6,75 months. 1,5 meter thick drainage blanket is also planned,
functioning as a horizontal channel to discharge water extracted by the Prefabricated Vertical
Drain (PVD).
Stability analysis using geostudio shows that the use of a single layer of geotextile tube
provides the most effective result, with a safety factor (SF) of 1,662. Manual analysis using the
method of slices yields an SF of 1,3, a sliding stability value of 3,44 > 1,5, and an overturning
stability value of 4,95 > 2, indicating that the breakwater design using a geotextile tube as the
core and rock as protection offers an efficient and stable solution

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Breakwater, Geotextile Tube, Tanah Lunak, Konsolidasi, Stabilitas Breakwater, Breakwater, Geotextile Tube, Soft Soil, Consolidation, Breakwater Stability
Subjects:	T Technology > TC Hydraulic engineering. Ocean engineering T Technology > TC Hydraulic engineering. Ocean engineering > TC333 Breakwaters
Divisions:	Faculty of Vocational > Civil Infrastructure Engineering (D4)
Depositing User:	Bima Ardyan Wijaya
Date Deposited:	04 Aug 2025 01:34
Last Modified:	04 Aug 2025 01:34
URI:	http://repository.its.ac.id/id/eprint/126228

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