Analisis stabilitas timbunan dengan metode soil replacement dan geosintetik pada proyek pembangunan Jalan Tol Jakarta-Cikampek II Selatan Paket 2A

The construction of embankments on soft soil often faces stability problems due to low shear strength and bearing capacity. This study aims to evaluate the effectiveness of the soil replacement method and geosynthetic reinforcement in improving embankment stability at STA 8+875 of the Jakarta–Cikampek II Selatan Toll Road Project Package 2A. The analysis was conducted using the Finite Element Method (FEM) through PLAXIS 2D and the Limit Equilibrium Method (LEM) through SLOPE/W. The study considered an embankment height of 8.7 m subjected to pavement and traffic loads of 24.4 kN/m² and seismic loading with a peak ground acceleration (PGA) of 0.1969g. Soil parameters were derived from N-SPT correlations, while the reinforcement utilized woven geotextile with an ultimate tensile strength of 200 kN/m. The results indicate that the existing embankment condition produced a safety factor (SF) of 1.035 under static loading and experienced collapse under combined static and seismic loading. The application of soil replacement to a depth of 3.5 m was unable to provide sufficient improvement, as the embankment still collapsed under loading conditions. Further analysis using SLOPE/W identified the most critical condition at slope 2 (right-to-left direction) with an SF of 1.088 under combined loading. Based on this condition, geosynthetic reinforcement requirements were determined and incorporated into the model. The combination of soil replacement and geosynthetic reinforcement increased the safety factor to 1.746 under static loading and 1.144 under seismic loading, satisfying the minimum stability requirement for dynamic conditions (SF ≥ 1.1). These findings demonstrate that the combined application of soil replacement and geosynthetic reinforcement is effective in enhancing embankment stability on soft soil foundations.