Soil mixing design methods and construction techniques for use in high organic soils.

PDFTech ReportBDK84-977-25BDV25-977-14Organic soilsSoil stabilizationMix designLiterature reviewsLaboratory testsField testsCement treated soilsFloridaFlorida. Dept. of TransportationMullins, GrayGunaratne, ManjrikerJohnson, KevinCostello, KellyBaker, SpencerMitchell, ElizabethVomacka, JeffMullins, MilesUniversity of South Florida. Dept. of Civil and Environmental EngineeringUS Transportation CollectionOrganic soils present a difficult challenge for roadway designers and construction due to the highcompressibility of the soil structure and the often associated high water table and moisture content. Forother soft or loose inorganic soils, stabilization via cement or similar binders (a method called soilmixing) has proven to be an effective and predictable solutions; the FHWA has published acomprehensive design manual for these techniques. Organic soils, however, are not addressed thereinto a level of confidence for design as organic soils do not follow the trends of inorganic soils.In short, the high porosity, high water content, and high levels of humic acids differentiate organic soilsfrom all other soils where soil mixing has been proven successful. To combat these effects, morecement content is required to bring the water/cement ratio down to acceptable levels and even morecement is required to offset the acidity.Extending the observations of past researchers, a threshold cement content was defined below whichno strength gain was achieved. This threshold was then defined as a cement content offset above whichthe measured strengths matched well with other soil types.This report presents the findings from a thorough literature search, laboratory bench tests, large scalelaboratory tests, field evaluation of past and on-going projects and concludes with recommendationsfor designing for soil mixing applications in highly organic soils