Analisis Pergeseran Lateral Dan Evaluasi Variasi Desain Fondasi Pada Tanah Lunak (Studi Kasus : Pembangunan Jalan Tol Semarang - Demak Seksi 2)

Ambarita, Friendly Alexander (2026) Analisis Pergeseran Lateral Dan Evaluasi Variasi Desain Fondasi Pada Tanah Lunak (Studi Kasus : Pembangunan Jalan Tol Semarang - Demak Seksi 2). Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pembangunan jalan tol pada daerah tanah lunak berpotensi menimbulkan permasalahan deformasi, khususnya pergeseran lateral pada sistem slab on pile yang berdekatan dengan timbunan dan lereng. Penelitian ini bertujuan untuk menganalisis penyebab pergeseran lateral tiang pancang pada area Ramp off serta mengevaluasi pengaruh variasi desain sistem fondasi terhadap respons struktur pada kondisi tanah lunak yang masih mengalami konsolidasi. Studi kasus dilakukan pada pembangunan Jalan Tol Semarang–Demak Seksi 2 dengan pendekatan analisis numerik menggunakan metode elemen hingga dua dimensi. Hasil analisis menunjukkan bahwa pergeseran lateral Ramp off dipengaruhi secara dominan oleh deformasi tanah lunak yang masih berlangsung pada fase konsolidasi jangka menengah, sehingga menyebabkan redistribusi tegangan dan kecenderungan deformasi menuju arah lereng. Respons struktur bersifat tidak independen, karena keberadaan dan pengaktifan tiang fondasi main road meningkatkan interaksi tanah–struktur dan memicu kenaikan pergeseran lateral pada area Ramp off. Pada akhir fase konsolidasi dua tahun tanpa pengaruh tiang main road, pergeseran lateral masih berada di bawah batas layanan SNI, namun meningkat dan melampaui batas layanan setelah adanya tiang main road. Evaluasi variasi desain sistem fondasi menunjukkan bahwa perubahan konfigurasi tiang memengaruhi kekakuan sistem dan tingkat interaksi tanah–tiang, namun tidak semua variasi efektif dalam menurunkan pergeseran lateral. Dari seluruh variasi yang dianalisis, satu konfigurasi desain mampu menurunkan pergeseran lateral hingga memenuhi kriteria layanan SNI tanpa menyebabkan kondisi tidak aman pada gaya aksial, momen lentur, dan penurunan vertikal. Variasi tersebut direkomendasikan sebagai alternatif perencanaan untuk pengendalian pergeseran lateral pada area expansion joint, sementara opsi mitigasi teknis lainnya dapat dipertimbangkan sebagai pengamanan tambahan apabila terdapat keterbatasan kondisi lapangan atau tahapan konstruksi.
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The construction of toll roads on soft soil areas is prone to deformation problems, particularly lateral displacement in slab-on-pile systems located adjacent to embankments and slopes. This study aims to analyze the main causes of lateral displacement of ramp-off pile foundations and to evaluate the effect of design variations of the foundation system on structural response under soft soil conditions that are still undergoing consolidation. The case study was conducted on the Semarang–Demak Toll Road Section 2 using a two-dimensional finite element numerical analysis approach. The results indicate that the lateral displacement of the ramp-off piles is dominantly influenced by ongoing soft soil deformation during the medium-term consolidation phase, which leads to stress redistribution and a tendency of soil deformation toward the slope direction. The structural response is not independent, as the presence and activation of the main road pile foundations increase soil–structure interaction and trigger additional lateral displacement in the ramp-off area. At the end of the two-year consolidation phase without the influence of the main road piles, the computed lateral displacement remains below the serviceability limit specified by the Indonesian standard. However, after the activation of the main road pile foundations, the lateral displacement increases and exceeds the serviceability limit, indicating an unsafe service condition. The evaluation of design variations of the pile foundation system shows that changes in pile configuration affect system stiffness and the level of soil–pile interaction, but not all variations are effective in reducing lateral displacement. Among the analyzed variations, one design configuration is able to reduce lateral displacement to meet the serviceability limit without causing unsafe conditions in axial force, bending moment, and vertical settlement. This configuration is recommended as an alternative design solution for controlling lateral displacement in the expansion joint area, while other technical mitigation measures may be considered as additional safeguards when field constraints or construction stages limit the implementation of the selected design.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	tanah lunak, pergeseran lateral, slab on pile, variasi desain, konsolidasi, interaksi tanah–struktur. ================================================================================================================================== soft soil, lateral displacement, slab on pile, design variation, consolidation, soil–structure interaction.
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA780 Piles and pile-driving
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Civil Engineering > 22101-(S2) Master Thesis
Depositing User:	Friendly Alexander Ambarita
Date Deposited:	27 Jan 2026 04:14
Last Modified:	27 Jan 2026 04:14
URI:	http://repository.its.ac.id/id/eprint/130634

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