Question

A soil is to be excavated from a borrow pit which has a density of 1.75 g/cc and w.c of12% .The G is 2.7 .the soil is compacted to that water content of 18% and dry density of 1.65 g/cc .For 1000m^3 of soil in fill,estimate quantity of soil to be excavated from the pit in m^3

Answer 1

Answer:

For the borrow pit:

Density, ρ1 = 1.75 g/cc

Water content, w1 = 12% = 0.12

Let the quantity of the soil to be excavated from the pit be denoted as “V1” and the dry density of the pit be denoted as “ρd1”.

∴ The dry density "ρd1" is given by,

ρd1 = ρ1 / [1+ w1] = 1.75/[1+0.12] = 1.75/1.12 = 1.562 g/cc

For the soil used in fill estimate:

Water content, w2 = 18% = 0.18

Dry density, ρd2 = 1.65 g/cc

Volume of the soil, V2 = 1000 m³

Now we know,

The dry density is inversely proportional to the volume, i.e.,

Ρd  ∝ [1/V]

∴ ρd2  / ρd1  = V1/V2

Substituting the given values

⇒ 1.65 / 1.562 = V1 / 1000

⇒ V1 = 1.05633 * 1000

⇒ V1 = 1056.33 ≈ 1056 m³

Thus the quantity of soil to be excavated from the pit is 1056 m³.