Hydroclimatic Context and Deterministic Stability of Weathered Limestone Road-Cut Slopes along the Maros-Bone Corridor, Indonesia

Abstract

Road-cut slopes in tropical carbonate terrain are affected by the interaction of geometry, weathering, material strength, and seasonal water input. This study evaluated two weathered limestone road-cut slopes along the Maros-Bone corridor, South Sulawesi, Indonesia, using engineering-geological observations, laboratory properties, the Simplified Janbu method, and independent regional rainfall data. Site 1 in Cenrana is approximately 15 m high with a 43° inclination, whereas Site 2 in Mallawa is approximately 18 m high with a 55° inclination. Representative parameters were c = 12 kPa, φ = 21°, and γ = 12.7 kN/m³ for Site 1 and c = 14 kPa, φ = 28°, and γ = 13 kN/m³ for Site 2. The calculated factors of safety were 1.043 and 1.002, indicating very limited stability margins. Regional climate records for 2023 showed 3,336 mm of annual rainfall over 132 rainy days, with 94.1% occurring from November to April and monthly peaks of 1,091 mm in February and 803 mm in January. The rainfall data were used as hydroclimatic context rather than hydraulic model input. The findings indicate that weathering and seasonal wetness may aggravate Site 1, while steep geometry is especially critical at Site