GROUND IMPROVEMENT DESIGN FOR LIQEUFACTION MITIGATION IN LOMBOK, NUSA TENGGARA BARAT

• Main Author: Rani Bilqis - NIM: 15514077, Zahra
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/31873
• Institution: Institut Teknologi Bandung

<p align="justify">Indonesia have vast oceans that is a great potential for infrastructure development. However, as a country which was located in an active tectonic system, it also has to face some major problems, such as earthquake, that needs to be considered. The phenomenon that may occur due to earthquake is liquefaction. The purpose of this research is to design a ground improvement for liquefaction mitigation. The subject of this research is liquefaction assessment and mitigation for of Lombok, Nusa Tenggara Barat, which was analyzed both quantitatively and qualitatively. Qualitative analysis was done based on historical and geological data. Meanwhile, quantitative analysis was done by considering soil stress parameter and SPT value to determine liquefaction based on safety factor (FS) calculation by Simplified Seed Method. If FS < 1.1, the location does not have liquefaction potency. However, if FS &#8805; 1.1, it means that the location has the liquefaction potency. Using that method, it was concluded that Lombok have a liquefaction potential. This research was then continued to determine the right ground improvement method that was chosen based on effective depth of improvement. Results showed that the soil depth that needs to be improved was 10 m and 12 m so that the chosen methods were vibrocompaction and stone column. Both of these methods use vibration technique to compact the soil by inserting vibrating equipments into the ground. For stone column method, in addition to compaction with vibration techniques, part of the soil was also replaced with gravel. In this research, the ground improvement design was in a form of column diameter configuration, spacing between column, and the compaction pattern. For vibrocompaction design, the required spacing is 1,6 with column diameter 0,35 m for equilateral triangular pattern. Meanwhile, the stone column spacing is 2,6 m – 3,0 m for square pattern and 2,9 m – 3,0 m for equilateral triangular pattern with diameter column 1 m for both of compaction pattern.<p align="justify">