Control Stiffness Columns
We use Controlled Stiffness Columns (ridged inclusions) in conjunction with a transfer slab to improve the soil characteristics of soft formation soil, and reduce the imposed settlements of loads exerted by either upfill or structures.
The Process
Controlled Stiffness Columns are performed without soil removal, using a specially designed drilling tool that displaces the soil laterally toward the bore walls. This increases the density of the surrounding soils, and as such increases their bearing capacity and the potential for settlement.
On completion of a boring operation, the drilling string and the tool are extracted whilst weak concrete is pumped throughout the internal hollow pipe. A designed load transfer platform, consisting of either stabilised soils or imported aggregate with geo-grids, is placed over the columns. This effectively transfers the imposed loadings from the upfill or structure onto the improved formation soils and displacement columns.
Advantages when compared with our other deep ground improvement techniques:
- Very cost effective in certain soil conditions
- No shock and vibration during columns installation
- Easy to validate column integrity
- High daily production rate
Technical data
- Columns diameter: 250 to 750 mm
- Columns depth: up to 20m depending on soil diameter and consistency
Applications
Displacement columns can be used to improve the soil characteristics of soft formation soils and reduce imposed settlements under;
- Road and railway embankments
- Building and house foundations
- Storage tanks
- Slurry cut-off walls
- Hardstandings
- Bridge abutments
- Retaining walls
