A flownet below a dam consists of 24 equipotential drops and 7 flow channels. The difference between the

Q. A flownet below a dam consists of 24 equipotential drops and 7 flow channels. The difference between the upstream and downstream water levels is 6 m. The length of the flow line adjacent to the toe of the dam at exit is 1 m. The specific gravity and void ratio of the soil below the dam are 2.70 and 0.70, respectively. The factor of safety against piping is

(A) 1.67                      (B) 2.5                        (C) 3.4                       (D) 4

Ans: 4

Sol:

Nd=24

Nt=7

ΔH=6m

G = 2.70

e = 0.70

Factor of safety against piping