ANALYSIS AND DESIGN OF OIL TANK FOUNDATION IN LIQUEFIABLE SOIL USING STONE COLUMN

• Main Author: Rohimah, Ghifariyatu
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/48349
• Institution: Institut Teknologi Bandung

The Refinery Development Master Plan Program (RDMP) is one of the types of infrastructure needed to support economic growth to increase national energy. In this final project, design of soil improvement for tank foundation was proposed so that the tank can perform satisfactorily. Stone column was selected as ground improvement method that allows densification of liquefiable loose sand. The design process of stone column is based on column capability to dissipate excess pore water pressure in case of earthquake. This can happen because the permeability of the stone column is higher than the surrounding soil. Also, to mitigate liquefaction, the stone column will increase the stiffness of the soil which causes the Cyclic Stress Ratio (CSR) value to decrease, and in the installation process, the stone column will possibility to increase density of soil so that the Cyclic Resistance Ratio (CRR) value increases. Based on the design concept, the stone column configuration results are obtained in the form of a square, diameter stone column 0.8 meters with a spacing of 1.3 m and 1.5 m, and installation depth varies from 10 m to 14.5 m. Introducing stone column, which acts as stiff element in the ground and allows for sustaining higher stress, to the ground leads to significant reduction in settlement. The shallow foundations used for oil tanks are circular foundations with a diameter of 64 m and 0.95 m thick. After the soil is improved using stone columns, bearing capacity will increase to the bearing capacity of the composite system which results in a safety factor for all boreholes of more than 3. Various types of settlements have been evaluated in this work and they meet the design criteria. Modeling of the stone column and circular foundation was done using PLAXIS 2D V20 software.