Analisa Stabilitas Lereng Dan Penanganan Longsoran Pada Ruas Jalan Mota’ain – Henes – Motamasin Sta 159+580 Ditinjau Dari Aspek Efektivitas Struktur Perkuatan

Tahjudin, Ikhsan (2026) Analisa Stabilitas Lereng Dan Penanganan Longsoran Pada Ruas Jalan Mota’ain – Henes – Motamasin Sta 159+580 Ditinjau Dari Aspek Efektivitas Struktur Perkuatan. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Ruas jalan Mota’ain – Henes – Motamasin, khususnya pada STA 159+580, merupakan area strategis yang mengalami masalah ketidakstabilan lereng berulang. Meskipun telah dilakukan penanganan menggunakan struktur bronjong pasca longsoran tahun 2021, longsor kembali terjadi pada tahun 2024. Lokasi studi didominasi oleh Formasi Lempung Bobonaro yang memiliki karakteristik ekspansif dan rentan terhadap penurunan kekuatan akibat siklus basah-kering. Penelitian ini bertujuan untuk mengevaluasi faktor penyebab kegagalan struktur eksisting, menganalisis stabilitas lereng pasca kelongsoran, serta menentukan rekomendasi penanganan permanen yang efektif. Metodologi penelitian melibatkan investigasi geoteknik lapangan (bor log dan geolistrik), pengujian laboratorium, dan simulasi numerik menggunakan metode elemen hingga (Plaxis 2D). Analisis balik diterapkan untuk memvalidasi parameter kuat geser residual tanah pada saat keruntuhan. Evaluasi pemilihan alternatif perkuatan dilakukan menggunakan metode Multi-Criteria Decision Analysis dengan mempertimbangkan aspek teknis, biaya, lahan, dan kemudahan pelaksanaan. Hasil analsisi menunjukkan bahwa kegagalan struktur bronjong eksisting disebabkan oleh mekanisme ganda, yaitu degradasi kekuatan tanah menuju kondisi residual (kohesi c' = 10 kPa dan sudut geser φ' = 29˚) serta terjadinya gerusan hidrolis pada kaki struktur yang menurunkan Faktor Keamanan secara drastis menjadi 0,38. Kondisi stabilitas lereng pasca kelongsoran tanpa perkuatan berada pada tingkat kritis dengan SF sebesar 0,97. Berdasarkan simulasi berbagai skenario penanganan, direkomendasikan dua opsi utama: penggunaan Buffer Wall pasangan batu sebagai prioritas fungsional (Skor MCDA 4,30; SF 3,03) yang efisien secara biaya dan lahan, serta Dinding Penahan Tanah (DPT) dengan Bored Pile sebagai prioritas teknis (Skor MCDA 3,80; SF 1,97) untuk memberikan proteksi permanen terhadap risiko gerusan dan bidang gelincir dalam.
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The Mota'ain-Henes-Motamasin road section, specifically at STA 159+580, is a strategic area experiencing recurrent slope instability issues. Despite previous mitigation efforts using gabion structures following a landslide in 2021, a subsequent failure occurred in 2024. The study location is dominated by the Bobonaro Clay Formation, characterized by its expansive nature and susceptibility to strength degradation due to wet-dry cycles. This research aims to evaluate the factors causing the failure of the existing structure, analyze post-failure slope stability, and determine effective recommendations for permanent reinforcement. The research methodology involves field geotechnical investigations (boring logs and geoelectric surveys), laboratory testing, and numerical simulations using the finite element method (Plaxis 2D). Back-analysis was applied to validate the residual soil shear strength parameters at the time of failure. The selection of reinforcement alternatives was evaluated using Multi-Criteria Decision Analysis (MCDA), considering technical aspects, cost, land requirements, and ease of execution. The analysis results indicate that the failure of the existing gabion structure was caused by a dual mechanism: the degradation of soil strength towards a residual condition (cohesion c' = 10 kPa and friction angle φ' = 29˚) and the occurrence of hydraulic scouring at the structural toe, which drastically reduced the Safety Factor (SF) to 0.38. The post-failure slope stability condition without reinforcement remains at a critical level with an SF of 0.97. Based on simulations of various mitigation scenarios, two main options are recommended: the use of a Masonry Buffer Wall as a functional priority (MCDA Score 4.30; SF 3.03) due to its cost and land efficiency, and a Retaining Wall (DPT) with Bored Piles as a technical priority (MCDA Score 3.80; SF 1.97) to provide permanent protection against scouring risks and deep-seated failure.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Lempung Bobonaro, Stabilitas Lereng, Analisis Balik, Scouring, Plaxis 2D, Penanganan Longsor. Bobonaro Clay, Slope Stability, Back-Analysis, Scouring, Plaxis 2D, Landslide Mitigation.
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA749 Soil stabilization
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Civil Engineering > 22101-(S2) Master Thesis
Depositing User:	Ikhsan Tahjudin
Date Deposited:	23 Jan 2026 07:43
Last Modified:	23 Jan 2026 07:43
URI:	http://repository.its.ac.id/id/eprint/130234

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