61) What is the value of bulk unit weight if the soil’s moisture content is 20% & the dry unit weight of soil is 17 KN/m3.
a) 22.6 KN/ m3
b) 24.4 KN/ m3
c) 19.3 KN/ m3
d) 20.4 KN/ m3
Answer: d) 20.4 kN/ m3
- Dry unit weight of soil, γd = 17 KN/ m3
- Moisture content of soil, w = 20% = 20/100 = 0.2
- We know that,
Dry unit weight of soil = (Bulk Unit weigth of soil)/(1+Moisture Content)
- Symbolically, γd = γ/(1+w)
- After rearranging of above terms,
- we get, Bulk unit weight, γ = γd x (1+w)
γ = 17 x (1+0.2)
γ = 20.4 KN/ m3.