COMBINATION OF GEOCELL AND FULL DISPLACEMENT COLUMN AS A SOFT SOIL IMPROVEMENT METHOD (CASE STUDY OF TOLL ROAD PROJECTS IN WEST SUMATERA PROVINCE)

• Main Author: Awaliah Septianty, Dina
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/71238
• Institution: Institut Teknologi Bandung

Soft soils condition oftentimes causes problems in the construction of road embankments. Toll road in West Sumatra are located on soft soil locations with a depth of >10 meters. Embankment has been improved using the combination of Full Displacement Column (FDC) using Load Transfer Platform (LTP) of sand and geotextile materials. Afterwards, when embankment was constructed at half of the design height, a failure take place in the embankment. This incidents indicates load transfer system between FDC and LTP is not optimal, presence of water in the fill material, then expected arching effect does not occur. In this study, an evaluation of the performance of existing soft soil improvement methods was carried out, followed by an alternative design method, namely combination of FDC and geocell as LTP. The results of modeling using PLAXIS 2D show that geocells can increase the safety factor value by more than 1.5 and comply the 10-year operational permit settlement less than 10 cm. This condition is achieved using a combination of geocell (M =160 kN/m), 50 cm thickness (2 layers) with granular infill material and 2 layers of geogrids (Tult = 150 kN/m).