SEISMIC PERFORMANCE EVALUATION OF GROUND IMPROVEMENT USING DEEP SOIL MIXING METHOD AT GARONGKONG TRAIN STATION DURING THE 2018 PALU EARTHQUAKE

• Main Author: Baihaqi Pasaribu, Irsyad
• Format: Theses
• Language: Indonesia
• Subjects: Teknik sipil
• Online Access: https://digilib.itb.ac.id/gdl/view/77906
• Institution: Institut Teknologi Bandung

Liquefaction, a seismic phenomenon triggered by earthquakes, poses a significant threat to infrastructure. Indonesia, located at the convergence of three tectonic plates, is highly susceptible to earthquake-related disasters. Ground improvement methods are essential for mitigating liquefaction risks, with deep soil mixing (DSM) being a notable solution. This research endeavors to assess the seismic performance of the soil at Garongkong Port Station in Barru Regency, South Sulawesi, specifically within Zone 3 (STA 4+300 - STA 4+500). The evaluation centers on parameters such as the pore water pressure ratio (ru) and lateral soil displacement induced by dynamic loads, both before and after implementing deep soil mixing. Furthermore, we investigate the impact of deep soil mixing on acceleration spectra responses. This assessment encompasses a range of variations in the area replacement ratio (Ar) and shear modulus ratio (Gr) values of DSM piles, totaling 20 distinct scenarios. The analysis of liquefaction potential and lateral soil displacement is conducted through numerical simulations employing the MIDAS GTS NX finite element method, represented in a 2D plane strain model. Dynamic loading incorporates ground motion propagation data derived from the 2018 Palu Earthquake, with earthquake load propagation from bedrock to the soil surface being modeled using DEEPSOIL software. The findings reveal that the installation of DSM piles can reduce ground surface lateral displacement by up to 80% compared to conditions without improvement. DSM ground improvement also leads to a notable decrease in the average ru value, ranging from 49% to 54%. The variations in Ar (ranging from 20% to 50%) and Gr (also ranging from 20% to 50%) demonstrate that larger Ar and Gr values correspond to more substantial reductions in soil lateral displacement and ru values. However, as Ar and Gr values reach certain thresholds, the incremental benefits diminish. Additionally, the installation of DSM piles contributes to a 39% increase in acceleration spectra response compared to preimprovement conditions.