Stabilisasi Tanah Rentan Likuifaksi di Pesisir Pantai Menggunakan Mikroba Dengan Variasi Salinitas Air

Setyaningsih. P, Nur Ayu Diana Citra Dewi (2025) Stabilisasi Tanah Rentan Likuifaksi di Pesisir Pantai Menggunakan Mikroba Dengan Variasi Salinitas Air. Doctoral thesis, Institut Teknologi Sepuluh Nopember.

This is the latest version of this item.

[thumbnail of 7012211012-Dissertation_Thesis.pdf] Text
7012211012-Dissertation_Thesis.pdf - Accepted Version
Restricted to Repository staff only
Download (5MB)

Abstract

Penelitian ini dilakukan untuk mengatasi masalah likuifaksi di wilayah pesisir pantai yang rentan terhadap bahaya likuifaksi, khususnya di kawasan Bandara Internasional Yogyakarta (YIA). Likuifaksi merupakan fenomena yang sering terjadi pada tanah berpasir dengan kepadatan rendah, terutama ketika terkena beban dinamis seperti gempa bumi. Pendekatan inovatif menggunakan metode biocementing berbasis Microbially Induced Calcium Calcite Precipitation (MICP) dipilih untuk meningkatkan stabilitas tanah. Proses ini melibatkan mikroba Bacillus safensis, fly ash kelas C yang berasal dari PLTU Pacitan sebagai sumber kalsium, serta variasi salinitas air (0%, 1%, 2%, dan 3,4%) yang disesuaikan dengan kondisi lapangan. Metodologi penelitian mencakup proses biostabilization melalui penambahan mikroba dan bahan kimia, diikuti dengan pengujian laboratorium. Evaluasi dilakukan menggunakan uji triaxial cyclic untuk mensimulasikan beban dinamis dan mengukur ketahanan tanah terhadap likuifaksi. Selain itu, uji kuat geser langsung (Direct Shear) dan kuat tekan bebas (UCS) digunakan untuk mengevaluasi kekuatan tanah setelah stabilisasi. Variasi salinitas air menjadi fokus utama dalam penelitian ini untuk mengidentifikasi kadar optimal dalam proses biosementasi. Hasil penelitian menunjukkan bahwa penambahan salinitas hingga 2% mampu meningkatkan pembentukan CaCO₃ secara signifikan, yang berkontribusi pada peningkatan kekuatan tanah dan ketahanan terhadap likuifaksi. Pada kadar salinitas 3,4%, efektivitas biocementation mulai menurun. Fly ash dengan komposisi 35% terbukti memberikan performa terbaik dalam meningkatkan stabilitas tanah. Proses MICP menghasilkan presipitasi CaCO₃ yang efektif mengisi pori-pori tanah dan meningkatkan kekakuan struktur partikel. Selain itu, ditemukan bahwa proses MICP bersifat non-ureolitik, menghasilkan vaterite tanpa penambahan urea. Secara keseluruhan, metode ini berhasil menurunkan kerentanan likuifaksi secara signifikan, dengan batas optimal salinitas ditetapkan pada kadar 2%.
===================================================================================================================================
This study was conducted to address the issue of liquefaction in coastal areas vulnerable to this hazard, specifically in the vicinity of Yogyakarta International Airport (YIA). Liquefaction is a common phenomenon occurring in loose sandy soils, particularly when subjected to dynamic loads such as earthquakes. An innovative approach employing a biocementation method based on Microbially Induced Calcium Calcite Precipitation (MICP) was selected to enhance soil stability. This process involves the bacterium Bacillus safensis, Class C fly ash sourced from the Pacitan coal-fired power plant as a calcium source, and variations in water salinity (0%, 1%, 2%, and 3.4%) adjusted to field conditions. The research methodology includes a biostabilization process through the addition of microbes and chemical agents, followed by laboratory testing. Evaluation was performed using cyclic triaxial tests to simulate dynamic loading and measure soil resistance to liquefaction. Additionally, direct shear and unconfined compressive strength (UCS) tests were conducted to assess soil strength after stabilization. The variation in water salinity was a primary focus to identify the optimal concentration for the biocementation process. Results indicate that salinity levels up to 2% significantly enhance CaCO₃ precipitation, contributing to increased soil strength and liquefaction resistance. At a salinity of 3.4%, the effectiveness of biocementation begins to decline. Fly ash at a composition of 35% demonstrated the best performance in improving soil stability. The MICP process produced CaCO₃ precipitates that effectively filled soil pores and increased particle structure stiffness. Furthermore, it was found that the MICP process is non-ureolytic, producing vaterite without the addition of urea. Overall, this method successfully reduced liquefaction susceptibility significantly, with the optimal salinity threshold established at 2%.

Item Type: Thesis (Doctoral)
Uncontrolled Keywords: Bacillus safensis, biocementing, fly ash, likuifaksi, MICP, salinitas, stabilisasi tanah, triaxial cyclic, Bacillus safensis, biocementing, cyclic triaxial, fly ash, liquefaction, MICP, salinity, soil stabilization.
Subjects: T Technology > TA Engineering (General). Civil engineering (General) > TA749 Soil stabilization
Divisions: Faculty of Civil Engineering and Planning > Civil Engineering > 22001-(S3) PhD Thesis
Depositing User: Unnamed user with email mahasiswa
Date Deposited: 08 Aug 2025 03:34
Last Modified: 08 Aug 2025 03:34
URI: http://repository.its.ac.id/id/eprint/124077

Available Versions of this Item

Actions (login required)

View Item View Item