méthode du perméamètre à charge constante

OBS: Perméamètres : Appareils de laboratoire destinés à mesurer le coefficient de perméabilité d'un échantillon de sol. Perméamètre à charge constante, perméamètre à charge variable.
OBS: Constant head (constant pressure head) : charge constante.

CONT: Determination of the water permeability of a geotextile using the constant head method - ASTM. This method can be used to determine both the coefficient of permeability, k, and the permittivity, [psi]. Preference is given, however, to the permittivity because the k-value is directly related to the thickness of the geotextile and the thickness varies strongly from geotextile to geotextile. Permittivity is defined as the filter velocity per unit of hydraulic gradient.
OBS: The principal types of apparatus for determining the coefficient of permeability of soil samples are ... the constant-head permeameter ... and the falling-head permeameter ... .