In this book strategies for using very soft organic clay as a fill material for road embankment constructions are compared, and an optimisation scheme is presented. Computer programs for simulation of evaporative drying, for simulation of consolidation, and for slope stability calculation were used to analyse clay behaviour. Field and laboratory testing programs for a trial embankment were set up in order to study the relations of parameters, to examine suitability and workability of the clay, and to verify the improvement methods. An optimisation technique was applied as a rational method for using very soft organic clay for road embankments leading to an economic construction. Also recommendations are presented based on a rational method for conditioning and emplacing very soft organic clay in a safe and economic way.