Perencanaan Struktur Dinding Penahan Tanah Tipe Kantilever dengan Perkuatan Boredpile Diameter 60 Cm sebagai Alternatif untuk Menanggulangi Longsor dengan Menggunakan Program Plaxis 2d (Studi Kasus: Perkebunan Nusantara, Sumatera Utara)

Abstract

Landslides are one of the most frequent geotechnical disasters in Indonesia, often causing significant losses in terms of infrastructure and economy. They are triggered by various factors such as geological conditions, steep topography, high rainfall, seismic activity, and poor soil stability. One such case occurred at the loading ramp area of a palm oil mill, which disrupted the production process and required geotechnical analysis to determine the appropriate slope reinforcement. This study focuses on the design of a cantilever retaining wall structure combined with bored pile reinforcement as an alternative solution. The analysis was conducted using two approaches: manual calculations based on slope stability theory and numerical simulations with PLAXIS 2D 2024.2, and the results of both methods were compared to evaluate the effectiveness of the proposed design. The results show that the existing slope has a safety factor (SF) below the required standard (SF < 1.5), indicating a critical and failure-prone condition. However, after the reinforcement was applied, the safety factor increased to 1.506 under static conditions and 1.106 under seismic loading, both of which met the minimum slope stability requirements. Therefore, it can be concluded that the use of a cantilever retaining wall with bored pile reinforcement is effective in improving slope stability and preventing potential recurrent landslides, while also ensuring smooth operational performance in the loading ramp area. Moreover, this approach can serve as a design reference for similar geotechnical problems in other locations.