WHAT IS SOIL SUCTION?

Soil Suction

Soil suction is considered as the summation of matric suction (ψ_{m) and osmotic suction (π).}

Soil suction is defined as the state of the soil when it is under reduced pressure.It is measured in terms of the height of the water column (h) suspended in the soil.

Soil Suction Formula

Soil suction can be represented as common logarithm of the height of the water column (h).The value of 'h' is substituted in centimeters.

 

Pf = log10 (h)

For example: The height of the water column is 100cm.Hence, the Pf value is given by:

 _{Pf = log10 (h)}

     _{= log10 (100)}

     _{= log10 (10^2)}

     _{= 2 x log10}

     _{= 2}

_{Similarly, for a height of column = 1 cm.}

Hence the Pf value is given by:

 Pf  = log10 (h)

 Pf   = log10 (1)

 Pf   = 0

Soil suction can also be represented in atm, kPa, kg/cm2 and bar.