Bulk volume = 3. Since there are 8 spheres in the unit cell. Grain volume = 8 x x /3) The porosity is therefore is. The interesting point is that the radii cancel in the formula and the porosity of packing uniform spheres is a function of packing only. Grain size distribution and grain sorting
Soil void ratio is the ratio of the volume of voids to the volume of solids: e = / Where V v is the volume of the voids , and V s is the volume of solids. Void ratio is usually used in parallel with soil porosity , which is defined as the ratio of the volume of voids to the total volume of the soil. The posoity and the void ratio are inter related as follows:
Fundamentals of Fluid Flow in Porous Media Chapter 2 Porosity: Laboratory Porosity Measurement A great many methods have been developed for determining porosity, mainly of consolidated rocks having intergranular porosity . Most of the methods developed have been designed for small samples. From the definition of porosity it is obvious that
Porosity is the percentage of void space in a rock. It is defined as the ratio of the volume of the voids or pore space divided by the total volume. It is written as either a decimal fraction between 0 and 1 or as a percentage. For most rocks, porosity varies from less than 1% to 40%. The porosity of a rock depends on many factors, including the rock type and how the grains of a rock are arranged.
Void space: e = Vvoid/Vsolid Primary porosity between grains Secondary porosity fracture or solution porosity Primary porosity Uniform spheres porosity constant, independent of particle size Can have different packing: Non uniform grains will have lower porosity because small grains fill void spaces between larger clasts. Spheres can form ...