Question

Water is flowing at a rate of 0.04 m^3/s in a soil sample of 12m thick and cross section of 50m^2. The coefficient of permeability is 1.6*10^-3m/s. What will be the seepage pressure?

(a) 50.76 kN/m^2

(b) 52.34 kN/m^2

(c) 55.34 kN/m^2

(d) 58.86 kN/m^2

This question was addressed to me by my school teacher while I was bunking the class.

My enquiry is from Seepage Pressure and Upward Flow in portion Seepage Analysis of Geotechnical Engineering I

Answer 1

Right choice is (d) 58.86 kN/m^2

Explanation: Given,

Discharge q=0.04 m^3/s

z=12m

Area A=50 m^2

coefficient of permeability k=1.6*10^-3m/s

the hydraulic gradient i is given by,

i=q/(kA)

i=0.04/(50*1.6*10^-3)

i=0.5

∴ ps =iγwz

ps =0.5*12*9.81

∴ ps =58.86 kN/m^2.