2021 : Subgrade Evaluation and Alternative Improvement of Road Stucture with the Prefabricated Vertical Drain (Pvd) and Geotextile Methods
Deris Faisa Ralindra ST, MT
The construction of the toll road as infrastructure that connects Balikpapan and Samarinda, has resulted in soil damage in the form of cracks and landslides at STA 4 + 825 to STA 10 + 575. The length of the crack is 1,120 meters with various types, locations and heights. In the STA span, area zoning is carried out based on soil type and depth. From 17.5 KM, the damaged road was divided into 6 zones. After evaluation, it was found that zones 1, 2, and 3 had reduction rate exceeding 2.5 cm/year. In addition, the stability of the embankment in zone 1 to zone 6 had value of Safety Factor less than 1.35, which means that the condition was not safe. In zones 1,2 and 3, soil improvement was carried out using Prefabricated Vertical Drain (PVD) method with 2.25 m distance and 20 m depth. While the reinforcement usesd geotextiles in all zones with variations in tensile strength and the number of layers as needed.