What type of soil is characterized by very high porosity and low strength?

Peat is a type of soil that forms in waterlogged conditions, where organic matter accumulates over time without fully decomposing. This results in very high porosity due to the high content of decomposed plant materials and a structure that contains many voids. However, peat is also characterized by low strength, making it unsuitable for heavy loads and construction purposes. Its unique properties mean that while it can hold water well, its ability to support structures is limited.

In contrast, silt, clay, and sandy soil do have unique characteristics but do not exhibit both very high porosity and low strength to the same extent as peat. Silt generally has moderate porosity, clay has low permeability but can be quite strong depending on moisture content, and sandy soils are known for good drainage and strength but typically do not reach high porosity like peat does. Thus, peat stands out as the soil type best fitting the description of having very high porosity and low strength.