In-Place Treatment of Foundation Soils

The state-of-the-art of seven special methods for the treatment of soils for the support of structures is reviewed. Whereas vibroflotation, compaction piles, blasting and grouting are limited mainly to the treatment of cohesionless soils, electro-osmosis, thermal treatment, and treatment with additives find primary application in the treatment of cohesive soils. Although blasting is usually the fastest and least expensive, compared with vibroflotation and compaction piles, the results are the least certain. Installation of stone column piles by vibroflotation has extended the range of application of this method into cohesive soils. Recently developed chemical grouts are now approaching the ideal in terms of viscosity and control of setting time. Mixed-in-place intrusion grouting appears to be a promising technique for construction of soil-cement piles in place. Additive stabilization of foundation soils for structures is used mainly in connection with grouting and electro-osmosis, with additional application to the treatment of expansive soils to shallow depths.