UPSC Civil Service Exam Questions - Engineering

Q1:

A flownet for an earth dam on impervious foundation consists of 4 flow channels and 15 equipotential drops. The full reservoir level is 15 m above the downstream horizontal filter. Given that horizontal permeability is 9 x 10-6 m/s and vertical permeability is 1 x 10-6 m/s, the quantity of seepage through the dam will be

A 36 ml/s/m

B 25 ml/s/m

C 20 ml/s/m

D 15 ml/s/m

ANS:A - 36 ml/s/m

Equivalent permeability.

ke =sq root ( kx * ky) =3 * 10^6 m/s.

Seepage q= ke x H x Nf/Nd.
= 12 x 10-6m3/s/m.
=12ml/s/m.