Analisis Geoteknik dan Alternatif Penanganan Tebing Limestone di Kawasan Wisata Pantai Tanah Barak

Abstract

The Tanah Barak Beach area in South Bali has emerged as a prominent tourist destination characterized by its unique road access cutting through natural limestone cliffs. However, the geological condition of the sub-vertical cliffs makes them highly susceptible to mechanical and chemical weathering, as evidenced by a rockfall incident in January 2025. This study aims to analyze the geotechnical parameters of the soil at Tanah Barak cliff, evaluate slope stability against potential landslides, and recommend appropriate mitigation alternatives. The research methodology commenced with field investigations, including borehole drilling to 30 meters, Standard Penetration Tests (SPT), and laboratory testing to determine the rock's physical and mechanical properties. Slope stability analysis was subsequently conducted using the Limit Equilibrium Method (LEM) in GeoStudio 2022 SLOPE/W under various loading scenarios: existing, saturated, and surcharge. Investigation results revealed a stratigraphy dominated by limestone formations with varying degrees of weathering (N-SPT values of 50 or greater) but possessing a Rock Quality Designation (RQD) of less than 10%, classified as very poor. Through slope safety evaluation, this study assesses landslide mitigation alternatives, both structurally and non-structurally, such as slope geometry modification (bench-cut), retaining walls, soil nailing reinforcement, and surface water management. These recommendations are expected to minimize the risk of slope failure while preserving the aesthetic value of the limestone cliffs to support sustainable tourism in Bali.