Numerical analysis of embankment resting on floating bottom ash columns improved soft soil

Abstract

The construction of embankment over soft clay is quite a challenging job for the geotechnical engineer, which may results in a large settlement, bearing failure and stability issues. Stone columns can be used to minimize the settlement and increase the bearing capacity in such conditions. This study was carried out to investigate the behaviour of bottom ash columns underneath embankments using numerical modelling. The soft soil improved with bottom ash columns under the embankment subjected to traffic-induced loading was simulated in Plaxis 3D foundation software. The study variables include three area replacement ratios (Ar) of 10%, 15% and 20% and two columns length of 5m and 7.5m. The results indicated that enlarging the Ar and length of columns significantly reduced the final settlement and consolidation time. The maximum settlement reduction of 58% was reported for the Ar of 20% with 7.5m column depth. The study suggests that bottom ash columns can be used to improve soft soil underneath the embankment.