Question

A flownet of a coffer dam foundation has 6 flow channels and 18 equipotential drops. The head of water lost during seepage is 6 m. If the coefficient of permeability of foundation is $4\times {10}^{-5}$ m/min, then the seepage loss per metre length of dam will be

• A. $2.16\times {10}^{-2}{m}^3/day$
• B. $6.48\times {10}^{-2}{m}^3/day$
• C. $11.52\times {10}^{-2}{m}^3/day$
• D. $34.56\times {10}^{-2}{m}^3/day$

Answer 1

The correct option is C $11.52\times {10}^{-2}{m}^3/day$

Seepage loss per metre length,

$q=k\times \frac{N_f}{N_d}\times H$

$Given,k=4\times {10}^{-5}m/min$

$4\times {10}^{-5}\times 24\times 60m/day$

$=0.0576m/day$

$\therefore$ $q=0.0576\times \frac{6}{18}\times 6$

$=11.52\times {10}^{-2}{m}^3/day$

$N_f$ is number of flow channels = 6.0

$N_d$ is number of equipotential drops = 18