Engineering properties of peat and organic soils - Geotechnics of Organic Soils and Peat - page 56

Figure 3.9 a) Casagrande apparatus ( Source : http:// www.env.auckland.ac.nz/uoa/engineering-geology-
equipment), (b) cone penetrometer ( Source : http://www.ramaas.in/products.php?id=3) and
(c) plastic limit ( Source : http://www.denichsoiltest.com/Plastic-Limit-Test.html).

has a higher bulk density than fibrous peat. For instance, in the former it can range
up to 10 kNm − 3 , whilst in woody peat it may be half this figure. Table 3.5 shows the
typical unit weight for various soils.
Dry density, ρ d (dry unit weight, γ d ) is mass, M s (or weight of solid particle), over
total volume ( V ):

ρ d = M s /V (3.6)

Dry density is a more important engineering property of peat, influencing its behaviour
under load. The dry density itself is influenced by the effective load to which a deposit