Design of Ash Bund for Augmentation of Ash Pond by Raising Height of Ash Bund

Although fly ash from thermal power plants is being utilized by the construction sector, use of coarse pond-ash is very limited. Over the years the accumulated ash consumes dyke capacity—compelling its augmentation. As many of ash dykes have limited space around, raisings is possible only at the upstream, i.e., on settled ash—which makes the design and construction of raisings critical. The current paper presents augmentation of the existing ash bund at Lanco Amarkantak Power Limited, Korba, India—where 4000 tons of ash- slurry is deposited per day. The ash dyke is about 1 km × 0.5 km in dimension without any compartments. To meet future demand, raisings up to 9 m was planned on the upstream. A divide bund was also proposed and constructed for operational continuation. A detailed laboratory study, by modeling was conducted, to assess load–settlement behavior of the pond-ash—as field test results were not in agreement with ash behavior at site. Two decant systems were also required to designed, where ground improvement for decant structure and pipe line was necessary. It has to be achieved by both, preloading and by use of geocells. Dumping of daily ash slurry and utilization of dry-ash was also challenging simultaneously with construction.