Question

An extended layer of soil with homogeneous rounded grains has 10% of the material finer than 0.07 mm. The constant to be adopted to determine its permeability has been recommended as 750. What is its permeability?

• A. 30.18m/day
• B. 317.54 m/day
• C. 31752m/day
• D. 31.752 m/day

Answer 1

The correct option is D 31.752 m/day

$k=C{D}_{10}^2$

$k=750\times (0.07{)}^2=3.675m/day$

Note: As per Allen Hazen

$k=C{D}_{10}^2$

Where C = 100

$D_{10}$ is in cm

and k is in cm/sec

Similarly if we solve this equation

then $k=750\times (0.007cm{)}^2$

$=0.03675cm/sec$

$=0.03675\times {10}^{-2}m/day\times 24\times 3600$

$=31.752m/day$