ANALISIS NUMERIK KELONGSORAN LERENG SISI JALAN AKIBAT HUJAN Studi Kasus Keruntuhan Lereng Sisi Jalan Poros Sungguminasa-Sinjai, Km 109 Makassar

Abstract

Every year during the rainy season, rainfall-induced failures of roadside slopes frequently occur in some parts of
connecting roads among districts through hilly areas in South Sulawesi, Indonesia. These occurrences particularly
endanger people on the roads, people living next to the slopes and distract traffic fluency through the roads. This research
aimed at determining main factors triggering the slope failures. One of the sites, a main road connecting between
Sungguminasa and Sinjai (both district cities), Km 109 from Makassar (capital city of South Sulawesi Province), was
chosen as this research location. Field and laboratory soil testing were conducted to obtain soil parameters required to
perform the analyses of the slope failure mechanisms. Rainfall data from the closest rain gauge station to the site were
also collected to consider in the analyses. Numerical analyses using commercial software SV Flux coupled with SV
Slope were performed to examine the slope failures triggered by rainstorms. The analyses revealed that a particular
stratification of surface soils with silt layer (changing its thickness with the slope level, thicker layer into the slope crest)
overlying clay layer existing at the roadside slope greatly contribute to the slope failure.