Four samples, each having a void ratio of 0.76 and a specific gravity of 2.74, have degrees of saturation (S) of 85, 90, 95, and 100%. Determine the total (wet/moist) unit weight (γt) in pcf for each of the four samples.

a) γt = 120.107 lbf/ft³

b) γt = 121.455 lbf/ft³

c) γt = 122.803 lbf/ft³

d) γt = 124.150 lbf/ft³

Explanation:

Given:

e = 0.76

Gs = 2.74

γw = 62.43 lbf/ft³

a) S = 85%

b) S = 90%

c) S = 95%

d) S = 100%

We can apply the formula

γt = γw * (Gs+S*e) / (1+e)

a) γt = (62.43 lbf/ft³) * (2.74+0.85*0.76) / (1+0.76)

γt = 120.107 lbf/ft³

b) γt = (62.43 lbf/ft³) * (2.74+0.90*0.76) / (1+0.76)

γt = 121.455 lbf/ft³

c) γt = (62.43 lbf/ft³) * (2.74+0.95*0.76) / (1+0.76)

γt = 122.803 lbf/ft³

d) γt = (62.43 lbf/ft³) * (2.74+1*0.76) / (1+0.76)

γt = 124.150 lbf/ft³