PERENCANAAN DAN EVALUASI STRUKTUR BRONJONG UNTUK PENANGANAN LONGSORAN BADAN JALAN RUAS WAGHETE - MOANAMANI ( KM 219 + 600 )

Abstract

This study discusses soil stability and landslide mitigation efforts on the Waghete–Moanamani road section at KM 219 + 600 in the Papua Tengah Province. Road damage caused by slope failures is a common problem in regions with steep hilly topography, such as in Papua Tengah. One of the locations that experienced road displacement and settlement occurred at STA 219+600 on the Waghete–Moanamani section. This condition is influenced by high rainfall intensity, steep slope gradients, weak residual soil characteristics, and inadequate drainage systems. Therefore, this study aims to design and evaluate the performance of a gabion structure as an effective and sustainable solution for landslide mitigation at the site. The research methods include topographic surveys, laboratory testing of soil characteristics, bore log data and N-SPT values, as well as slope stability analysis using the simplified Bishop method. The analysis was conducted for two conditions, namely before and after reinforcement using gabion structures. The design parameters refer to SNI 8460:2017, with gabion dimensions of 2.00 × 1.00 × 0.50 m, wire diameter of 3 mm, and infill stone with a unit weight of 2.2 tons/m³. The evaluation covers stability against overturning, sliding, and bearing capacity. The analysis results show that after reinforcement with gabion structures, the factor of safety increased to 1.79 against overturning, 1.72 against sliding, and 2.74 against bearing capacity, all of which are above the minimum safety limit (≥ 1.5). This proves that the use of gabion structures is effective in improving slope stability and resisting soil mass movement at the study site. Thus, gabions can be considered an efficient, flexible, and economical technical solution for landslide mitigation on roadways in areas with similar geotechnical conditions.