Trans Sumatra Toll Road (JTTS) is one of the most important infrastructure projects in Indonesia. One of the main sections of JTTS is the Rengat - Pekanbaru Toll Road, Pekanbaru Ring Section (Pekanbaru Junction - Pekanbaru Bypass). Existing conditions at Sta 176+775 - Sta 176+975 are dominated by oil palm plantations with soft soil layers in the form of organic soil to a depth of 1.0 meter; the layer below is clay with medium to stiff consistency. The existing treatment plan is preloading embankment with PVD and 1,0 m deep subgrade replacement. In this study, alternative planning calculations were carried out with variations of subgrade replacement up to 0.5 m and 1,0 m thickness. The study results show that the most cost-optimal treatment design is the treatment design without replacement with geotextile reinforcement. The thicker the subgrade replacement, the smaller the compression and rate of settlement. In terms of embankment reinforcement, the thicker the subgrade replacement, the less reinforcement is required. The thickness of subgrade replacement also affects the cost of the work, the thicker the subgrade replacement, the higher the cost of the work.

ASTM Annual Book. (1992). Standard Classification of Peat Samples by Laboratory Testing (D4427-92), ASTM, Section 4, Volume 04.08 Soil and Rock. Philadelphia.

Dhianty, E., & Mochtar, I. B. (2018). Perumusan indeks pemampatan sekunder dan metode menghilangkan pemampatan sekunder pada tanah lempung. ITS. Surabaya.

Dhowian, A,W and T.B. Edil (1980). “Consolidation Behaviour of Peat”. GeatechnicalTesting Journal, Vol.3. No. 3. pp 105-144.

Gibson, R.W., Lo, K.Y (1961). A Theory of Consolidation of Soils Exhibiting SecondaryCompression. Acta Polytecnica Scandinavia.

Kementrian PUPR. (2020). Spesifikasi Umum Untuk Jalan Bebas Hambatan dan Jalan Tol.

Mochtar, NE. et al. (1999). “Aplikasi Model Gibson & Lo untuk Tanah Gambut Berseratdi Indonesia”. Jurnal Teknik Sipil, ITB, Vol. 6 N0. 1.

Mochtar, I. B. (2000). Teknologi Perbaikan Tanah dan Alternatif Perencanaan pada Tanah Bermasalah (Problematic Soils). ITS Press. Surabaya.

Naval Facilities Engineering Command. (1986). NAVFAC Design Manual 7.02 -. Government Printing Office. U.S.

Peraturan Menteri Pekerjaan Umum Dan Perumahan Rakyat Nomor 5 Tahun 2023. Persyaratan Teknis Jalan Dan Perencanaan Teknis Jalan.

PT Hutama Karya (Persero). (2023). Kontrak Perjanjian Pelaksaan Pekerjaan Pembangunan Pembangunan Jalan Tol Trans Sumatera Ruas Rengat - Pekanbaru Seksi Lingkar Pekanbaru (Juction Pekanbaru - Bypass Pekanbaru).

Zaika, Y., & Kombino, B. A. (2010). “Penggunaan Geotekstil Sebagai Alternatif Perbaikan Tanah Terhadap Penurunan Pondasi Dangkal”. Jurnal Rekayasa Sipil / Volume 4, No.2– 2010 ISSN 1978 – 5658, 91-98.