Combined Effects of Vertical Drain and Pre-loading to Reduce the Number of Geotextile Reinforcement for Road Embankment Design

The study of the behavior of embankments reinforced by geosynthetic construction on soft clay soil with and without a prefabricated vertical drain is described. The effect of a pre-loading with stage construction method to construct the embankment, the gain of bearing capacity, as well as the depth of compressible soil was also considered in this study. The limit equilibrium using Bishop and Fellenius methods was used in this study to determine the stability of the embankment. Vertical drain installation, combined with the stage construction method, substantially reduces the number of geotextile reinforcements needed. The number of geotextiles can be reduced by up to twice that compared with foundation soil without PVD. Furthermore, the combined use of geotextile and PVD can improve the performance of embankment height as well as increase the critical height of the embankment with geotextile reinforcements. Without PVD, the embankment will be safe against landslides (without geotextile) of less than 3.5 meters. When using PVD, the embankment critical height can increase by up to 7 meters. This condition occurs when the embankment is constructed using the stage construction method, geotextile reinforcement, as well as PVD installation for soil improvement.