Soil liquefaction beaches, dunes, and areas where windblown silt (loess) and sand have accumulated. Examples of soil liquefaction include quicksand, quick clay, turbidity currents and earthquake-induced liquefaction. Depending on the initial void ratio, the soil material can respond to loading either strain-softening or strain-hardening. Strain-softened soils, e.g. loose sands, can be triggered to collapse, either monotonically or cyclically, if the static shear stress is greater than the ultimate or steady-state shear strength of the soil. In this case "flow liquefaction" occurs, where the soil deforms at a low constant residual shear stress. If the soil strain-hardens, e.g. moderately dense to dense sand,
Polish Soil Classification effect of specific groups of soil forming processes. Soil types are divided into subtypes. Geological origin of bedrock described by "rodzaj gleby" describes geological origin and properties of material from which the soil was formed. It is not the same as soil family from USDA Soil Taxonomy. Examples can be: granitoid, basalt, amphibolite, sandstone, limestone (with specified period of formation), gypsum, glacial till, sandur sand, loess and others. Sizes of soil particles and texture of soil material are very similar to USDA classification. It makes possible correlating results of particle size analysis of soils described using USDA and Polish Soil