Design Alternatives for Semarang-Demak Freeway Sections on Very Soft Soil (Case Study: Section 1A STA 8+314 - STA 8+494 and Section 1B STA 2+850 - STA 3+010)

Dekasman, Laode Vizenthe Athilla Lemo (2025) Design Alternatives for Semarang-Demak Freeway Sections on Very Soft Soil (Case Study: Section 1A STA 8+314 - STA 8+494 and Section 1B STA 2+850 - STA 3+010). Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pembangunan Jalan Tol Semarang-Demak menghadapi tantangan geoteknik yang signifikan karena kondisi tanah yang sangat lunak di sepanjang Seksi 1A dan 1B, masing masing dibangun di atas tambak pesisir dan Laut Jawa. Untuk mengatasi hal tersebut, Seksi 1A (STA 8+314 – STA 8+494) didesain dengan struktur slab-on-pile, namun pada saat pelaksanaannya, tiang-tiang pancang ditemukan bisa menembus dasar laut secara tidak terkendali karena kondisi tanah dasar yang sangat lunak. Oleh karena itu, desain alternatif timbunan ringan (mortar busa) dipertimbangkan. Pada sisi lainnya, Seksi 1B (STA 2+850 – STA 3+010) menggunakan timbunan tanah di atas matras bambu yang dikombinasikan dengan tanggul laut, dengan perbaikan tanah menggunakan sistem preloading yang dikombinasikan dengan PVD dan tiang pancang bambu sebagai perkuatan tanah. Meskipun demikian, ada beberapa asumsi yang dibuat dalam perencanaan eksisting yang harus diperiksa untuk memastikan mereka memenuhi persyaratan. Selain itu, kemiringan lereng eksisting adalah 1:5, sehingga membutuhkan lahan yang relatif luas dan mahal. Mempertimbangkan hal-hal tersebut, tugas akhir ini meliputi pengumpulan data sekunder, studi literatur, analisis data tanah, desain alternatif timbunan ringan untuk Seksi 1A, evaluasi timbunan eksisting, perbaikan dan perkuatan tanah, dan alternatif lereng yang lebih curam untuk Seksi 1B, serta perbandingan biaya. Alternatif timbunan ringan terbuat dari mortar busa dan akan menggunakan PVD dan perkuatan micropile jika diperlukan. Selain itu, untuk Seksi 1B, jika asumsi desain eksisting bahwa Sc = 30% Hfinal tidak tepat, maka desain preloading akan direvisi, sementara jika desain PVD eksisting terbukti tidak dapat menghilangkan pemampatan yang ada dalam waktu 6 bulan, maka desain PVD akan direvisi. Perkuatan tanah dengan geotekstil sebagai tambahan dari perkuatan eksisting akan didesain jika diperlukan. Hasil dari studi ini adalah desain timbunan yang stabil, aman dan efisien untuk Jalan Tol Semarang Demak Seksi 1A (STA 8+314 – STA 8+494) dan Seksi 1B (STA 2+850 – STA 3+010).
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The construction of the Semarang-Demak Toll Road faces significant geotechnical challenges due to the very soft soil conditions along Sections 1A and 1B, which are built over coastal swamps and over the Java Sea respectively. To resolve the situation, Section 1A (STA 8+314 – STA 8+494) was designed as a slab-on-pile structure, however during implementation, the piles may unexpectedly penetrate the seabed uncontrollably due to the very soft existing soil. Therefore, an alternative design of light embankment (foam mortar) is considered. Conversely, Section 1B, specifically Zone J (STA 2+850 – STA 3+010) utilizes a soil embankment above bamboo mattresses combined with a sea wall, with soil improvement using the preloading system combined with PVDs and bamboo piles for soil reinforcement. Nonetheless, there are some assumptions made in the existing design that must be checked to ensure they meet requirements. Furthermore, the existing slope is 1:5, requiring a relatively large and expensive land area. Considering those points, this final project includes secondary data collection, literature study, soil data analysis, alternative design of light embankment for Section 1A, evaluation of existing embankment, soil improvement and reinforcement, and its steeper slope alternative for Section 1B, and finally cost comparison. The light embankment alternative is made of foam mortar and will use PVD and micropile reinforcements if required. Moreover, for Section 1B, if the existing design’s assumption that Sc = 30%Hfinal is incorrect, the preloading design will be revised, whilst if the existing PVD design proves unable to remove settlement within 6 months, the PVD design will be corrected. Soil reinforcement using geotextiles in addition to existing reinforcements is designed if necessary. The result of this study is a stable, safe and efficient embankment design for Semarang-Demak Toll Road Section 1A (STA 8+314 – STA 8+494) and Section 1B (STA 2+850 – STA 3+010).

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Foam Mortar, Geotextile, Light Embankment, Micropile, Preloading, PVD, Slope, Toll Road, Cerucuk, Geotekstil, Kemiringan Lereng, Mortar Busa, Jalan Tol, Preloading, PVD, Timbunan Ringan
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA455.S6 Soil (Materials of engineering and construction) T Technology > TA Engineering (General). Civil engineering (General) > TA749 Soil stabilization
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Civil Engineering > 22201-(S1) Undergraduate Thesis
Depositing User:	Laode vizenthe athilla lemo dekasman
Date Deposited:	28 Jul 2025 05:27
Last Modified:	28 Jul 2025 05:27
URI:	http://repository.its.ac.id/id/eprint/122141

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