Geotechnical Classification of Peats and Organic Soils Available to Purchase

On reviewing the literature on peat classification, it becomes evident that most of the existing classification systems are based on the use of peats and organic soils as a growing medium in horticulture, agriculture, and forestry, or as a horticultural additive (peat moss), or as a fuel. One exception is the Radforth classification system for peat, which does pertain to engineering applications. Since this system is not based on geotechnical properties, however, it is not in itself sufficient for geotechnical classification.

The term peat as used today also includes a vast range of organic soils: from jelly-like, almost liquid muds whose organic content may not even originate from peat, to extremely coarse-fibrous meshes of woody remnants and fibers. The mud is often referred to as an amorphous-granular peat and the woody mesh as a fibrous peat. These are the only two terms that have been generally adopted by geotechnical engineers, with the inevitable results that each term covers a large range of materials and that considerable overlapping occurs.

An attempt is made in this paper to distinguish between various peats and organic soils on the basis of geotechnical engineering considerations. The existing von Post and Radforth systems are examined with respect to geotechnical applications. These systems are supplemented with routine geotechnical tests yielding numerical values for classification purposes.