Dry or Wet Soil Mixing?

Wet VS Dry Soil Mixing   

Wet soil mixing involves the mixing of a liquid cement grout with the soil whereas dry soil mixing involves the addition of dry cement as a powder.

GDL offer Wet Soil Mixing as it is much more suited to UK soils. Below we list the differences between each: 

Initial water content of the soil to be treated
Cohesive soils moisture content (w) = 60-200% are best suited for dry process. Lower limit of 20% generally for sufficient moisture available to facilitate hydration.

Quality of mixing
Wet process normally provides better homogeneity of stabilised soil owing to easier distribution of slurry across the column area, pre-hydration of cement and longer mixing time.

Compressive strength of the soil-binder mix
Higher strength more reliably obtained with wet process (except in very wet soils).

Ability to penetrate to stiffer soil layer
Much higher for wet process owing to lubrication of injected slurry and high rig torque.

Stratified soils
Wet mixing can provide more uniform strength along the column length due to partial soil exchange / movement in the vertical profile; quality control generally more difficult in dry mixing.

Use of combined binders / industrial by-products
Frequently used in dry and wet processes particularly GGBS.

Column reinforcement
Possible in wet process.

Air temperature below 0°C
Dry process is significantly less effected by low temperatures as compressed air is used to transport binder.