Evaluasi Stabilitas Timbunan Dengan Soil Replacement Granular dan Geotextile Di Atas Tanah Lunak Menggunakan Finite Element Method (Studi Kasus: Proyek Jalan Tol Bogor - Ciawi - Sukabumi Seksi 3B STA. 0 + 400 s/d STA. 0 + 500)

Salsabila Kirana Raharja, Ir. Dian Sestining Ayu, S.T., M.T.

2025 | Tugas Akhir | D4 TEKNIK PENGELOLAAN DAN PEMELIHARAAN INFRASTRUKTUR SIPIL

Pembangunan Jalan Tol Bogor–Ciawi–Sukabumi (Bocimi) Seksi 3B STA 0+400 – STA 0+500 menghadapi permasalahan tanah lunak dengan daya dukung rendah, ditunjukkan oleh nilai CBR < 6>soil replacement granular dan geotextile woven serta non-woven dengan pendekatan Finite Element Method (FEM) 2D.

Analisis dilakukan pada tiga kondisi: eksisting tanpa perkuatan, perkuatan konservatif (14 lapis geotextile dan replacement 2 meter), dan desain optimasi (10 lapis geotextile dan replacement 2 meter). Hasil menunjukkan bahwa kondisi eksisting tidak stabil dengan faktor keamanan 0,6239 dan penurunan -1,164 m. Setelah perkuatan, nilai faktor keamanan meningkat menjadi 2,699 dan penurunan berkurang menjadi -0,292 m. Desain optimasi dengan 10 lapis geotextile menunjukkan hasil yang tetap aman dan efisien.

Kombinasi metode perkuatan tersebut terbukti efektif dalam meningkatkan stabilitas dan mengurangi penurunan timbunan. Metode FEM 2D memberikan hasil analisis yang cukup akurat dan dapat dijadikan acuan perencanaan di lapangan.

The construction of the Bogor–Ciawi–Sukabumi (Bocimi) Toll Road Section 3B STA 0+400 to STA 0+500 faces challenges due to soft subgrade soils with low bearing capacity, indicated by a CBR value of less than 6% and an N-SPT value of 3. These conditions can lead to embankment instability and significant settlement. This study aims to evaluate the stability of embankments using granular soil replacement and woven and non-woven geotextiles, analyzed with the Finite Element Method (FEM) 2D.

Three conditions were analyzed: existing condition without reinforcement, conservative reinforcement (14 layers of geotextile and 2 meters of granular replacement), and an optimized design (10 layers of geotextile and 2 meters of granular replacement). Results show the existing condition is unstable, with a safety factor of 0.6239 and settlement of -1.164 m. After reinforcement, the safety factor improved to 2.699 and settlement decreased to -0.292 m. The optimized design with 10 geotextile layers remains safe and more material-efficient.

The combination of granular replacement and geotextile proved effective in improving stability and reducing settlement. FEM 2D analysis provided reliable results and can serve as a reference for design and implementation in soft soil areas.

Kata Kunci : embankment, soft soil, soil replacement, geotextile, slope stability, settlement, FEM 2D.