Analysis of Road Embankment Stability Using Geotextile Reinforcement (Study Case at STA 5+325 of Tawang-Ngalang Segment IV Road and Bridge Construction)

Abstract

Tawang-Ngalang Segment IV Road and Bridge Construction in Gunungkidul Regency, Yogyakarta, is constructed to connect the city and suburban areas in southern Yogyakarta for a more effective way of travel. Gunungkidul regency is mountainous area, which means uneven area for construction. Therefore, excavation and embankment are necessary to provide little to no difference for the road elevation. This research will be focused on the safety of embankments structure. The study case taken is embankment on STA 5 + 325 with 6.75 in height. Using secondary type of data taken from PT. Geomine Bara Studio also laboratory and detailed engineering drawing data from PT. Aneka Dharma Persada. The objective of this research is to calculate the safety of embankment structure and to provide an alternative for the embankment angle for a safer road construction afterwards. Therefore, the embankment will be reinforced with geotextile with internal angle variations, and analysed with Fellenius method for static calculation, and PLAXIS as the instrument of Finite Element Method (FEM). The result shows that the safety factor for internal angle 25° and 20° with no reinforcement using static calculation are both collapses. After geotextile in installed on the location, the safety factors are 1.402 and 1.483 respectively. As for the consolidation settlement occur on the site for internal angle 25° with no reinforcement and after being reinforced are 0.1905 m and 0.1813 m. While for internal angle 20° with no reinforcement and after being reinforced are 0.1845 m and 0.1764 m.