Experiences of dry soil mixing in highly organic soils

Soil mixing, or soil stabilisation, is a method of enhancing the geotechnical properties of suitable host soil through the addition of cementitious and/or pozzolanic binders in either dry or slurry forms. In dry soil mixing, the binder is injected into the soil in powder form using compressed air. Published laboratory experiences of stabilising highly organic soils in dry soil mixing laboratory trials are collated in this paper. A large database of stabilised strengths is compiled from which it emerges that cement and a cement/ground granulated blast furnace slag combination are the most suitable binders for peat soils, and that the ratio of mass of water to mass of binder and the von Post classification H value are important indicators of stabilised strength. The data provide a useful frame of reference for practitioners wishing to select an appropriate binder type and content for mixing trials in peat. Stabilised strength gain over time is discussed, as are issues such as soil temperature, binder temperature sensitivity and prestressing.