Defination & Expressions: What Is soil Parmeability To You - (CEC 212)

What can you say about a soil parmeability, According to our own defination in a simple and short form. it is a measure of ease with which water flows through rock and soil. with this defination you've successfully put down a correct thing.

The soil parmeability is mathematically express as follows:
 where;

   Q - Quantity of water flowing
   T - Time of Q to flow
   K - Coefficient of parmeability
   A - Area of cross section
   H - Hydraulics head accross soil
   L - Length of flow path throug soil
   i - Hydraulic gadient.

With this you successfully understand what soil parmeability is.

  Q/T = KA (H/L); Note: H/L is also known as i
i.e; Q/T = KAi
 make k subject of the formular
 K = Q/T / Ai

Example: A constant head parmeabily test has been run on a sand sample 250mm in length and 200m3 in area. with a head loss of 500mm, the discharge was found to be 250ml in 130sec. determine the coefficient of permeability of soil, if S.G of grains is 2.62 and dry wight of sand is 916g. find void ratio

Solutions;
Q = 250ML

T = 130sec

A = 200M

i = H/L = 500/250 = 2

250ML ---> MM = (250 X 1000)MM

 K = 250 X 1000/130 / 2000 X 2
 K = 0.5MM/S

TO FIND VOID RATIO;

VS = (916 X 1000) X 1000 / 2.62 X 1000
    = 350,000mm3

Vv = 250 X 2000 - 350,000
    = 150,000mm3

e = Vv/Vs

  = 150,000mm3/350,000
   = 0.428