5 Empirical Formula for Determination of the Coefficient of Permeability
The coefficient of permeability of soil(K) can also be computed from several empirical formulae, which are given below:
1. Jaky’s Formula
Jakey in 1944 found an empirical formula of ‘K’ for all soils; , Where is grain size (in cm) that occurs with the greatest frequency.
2. Allen Hazen’s Formula
, where C is a constant. The value of C is taken approximately equal to 100, when is expressed in cm.
3. Terzaghi’s Formula
Terzaghi (1955) developed the following formula for fairly uniform sands, which reflects the effects of grain size and void ratio.
, Where = Effective grain size.
4. Kozney’s Formula
, where = Specific surface of particles, = Viscosity, and = Constant( that is equal to 5 for spherical particles).
5. Louden’s Formula
Where a and b are constants, the value of which are 1.365 and 5.15 respectively for permeability at 10°C.