Civil Engineering

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;  K = 100 D_{m}^{2}  , Where  D_{m} is grain size (in cm) that occurs with the greatest frequency.

2. Allen Hazen’s Formula

 K = C D_{10}^{2}  , where C is a constant. The value of C is taken approximately equal to 100, when  D_{10} 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.

 K = 200 D_{e}^{2} . e^2  , Where   D_{e} = Effective grain size.

4. Kozney’s Formula

 K = \frac{1}{K_{k} \eta S_{s}^{2}} \times \frac{n^3}{1-n^3} , where   S_{s} = Specific surface of particles,    \eta   = Viscosity, and    K_{k}  = Constant( that is equal to 5 for spherical particles).

5. Louden’s Formula

 \Rightarrow log_{10} (KS_{s}^{2}) = a + bn

Where a and b are constants, the value of which are 1.365 and 5.15 respectively for permeability at 10°C.

Read Also:

1. Capillarity Permeability Test

2. Coefficient of Permeability of Soil by Constant Head Permeameter

3. Factors Affecting The Permeability

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