Abstract: Combined with the geological characteristics of soft soils in the flood plain formations, the difference in the strength mechanism of using CementFly ash and Gravel (CFG) column and sandgravel column are discussed in this paper. The comparisons are made among the bearing capacity of the soils surrounding the columns, axial capacity of the single column as well as the composite capacity of columns. The bearing capacity of the soilcolumn composite ground is optimized throughout this research.

Key words: Flood Plains, Low Strength Columns, Sandgravel Columns, blowfill foundation, Cone Penetration Testing, Static Pile Load Test