Theoretical Discussion of a Model of Permeability Based on Soil Particle Diameters

摘要

The permeability is a parameter widely studied by many researchers in area of soil mechanics. Its application to land routes is very important around the world, due to the interaction between the geomechanical behaviour and the change in the soil moisture, because of time variability in dry or wet conditions. The hydraulic conductivity or permeability of a soil is the speed at which a fluid is able to pass through the solid particles under a unit hydraulic gradient and once known, this property is an important parameter for the design of filter layers or for the development and implementation of drainage in the civil infrastructure. The hydraulic conductivity is generally measured by laboratory tests using soil samples with standardized methods or in field with specialized devices. Several authors have attempted to obtain mathematical models that are able to determine soil permeability. In order to obtain this permeability parameter, particle size distribution is include in the analysis. This paper compares a mathematical model published recently in literature, with results associated with these parameters obtained by many researchers around the world on basis of independent lab testing, of the model in question. Relations are established between particle size of the material and permeability coefficient. The analysis presented herein indicates that is necessary incorporation of other variables that affect permeability coefficient of soils, such as energy of compaction or void ratio, both are necessary to get a more accurate model and applicable to the solution of problems in soil mechanics.