A soil sample has a dry density of 8.5 kN/m³, specific gravity of solids G as 2.7 and voids ratio of 0.6. If the unit weight of soil is 50% saturated, then its bulk unit weight will be ______
a) 19.274 kN/m³
b) 23.034 kN/m³
c) 20.554 kN/m³
d) 21.428 kN/m³

Answer: c
Explanation: Given,
Dry density γ_d = 18.5 kN/m³
Specific gravity G=2.7
Void ratio e= 0.6
Degree of saturation = 50% = 0.5
Since, e = (W*G)/S
W = (e*S)/G=(0.6*0.5)/2.7=0.111
Bulk unit weight γ=γ_d(1+W)
γ=18.5*1.111=20.554 kN/m³.