ABSTRACT
This chapter provides a discussion of the more common compressible soil units. The natural soils which would commonly be classed as compressible include soft clays and silts, very loose to loose sands, peats and other soils with high organic content. Laboratory methods can usually be applied only to soils in which 'undisturbed' samples can be recovered, but some assessment of clean sand can be made if the field density is measured reliably and the sands are tested in the laboratory at field density. Uncontrolled filling can take many forms, including domestic or industrial waste placed into tip sites, building waste, excavated waste soil or rock, or dredged soils. Typical developments founded on compressible soils include road and rail embankments, storage tanks, and other structures which can be designed to tolerate significant settlement. Where compressible soils are shallow, compaction techniques combined with total or partial removal and replacement of the compressible soil can be considered.
