Capacity of Piles in Pond Ash Based on Model Pile Load Tests-Paper

Paper

Pdf Summary

The study investigates the ultimate load capacity of piles installed in pond ash, a coal-power by-product often stored in large ash ponds. Understanding pile–ash interaction could help repurpose abandoned ponds, including for solar installations where foundations must resist wind-induced uplift.<br /><br />Researchers conducted laboratory model pile load tests using reinforced concrete piles in pond ash collected from NTPC Ramagundam, India. Tests varied pile embedment length, ash density, and moisture condition; results were also compared with tests in sand. The ash beds were prepared at 85%, 90%, and 95% of maximum dry density, with additional dry and saturated tests. Loads were increased incrementally while settlement was recorded.<br /><br />Pile failure in pond ash was brittle, resembling behavior in cohesionless soils. Ultimate capacity increased with both ash density and pile embedment: a 67% increase in embedment length produced a 97% capacity increase under the test conditions. Capacity in pond ash was 46% of that in sand under comparable conditions. Saturation reduced capacity substantially: the saturated case was 57.05% lower than the optimum-moisture case and 24.60% lower than the completely dry case. The authors also suggest cast-in-place piles may perform better than driven piles in both bearing and frictional resistance.<br /><br />The findings indicate that pile capacity in pond ash depends strongly on density, embedment, and moisture. Because the work used laboratory-scale models, further research is needed to assess scale effects and verify performance through full-scale field tests.

Keywords

pond ash

pile load capacity

ultimate load

reinforced concrete piles

ash density

embedment length

moisture condition

wind-induced uplift

foundation design

laboratory model tests