Calculation of Void Ratio of a Dry Soil Sample

Given data:
Weight of soil sample (W) = 100 g
Volume of soil sample (V) = 60 ml
Specific gravity (G) = 2.5

Void ratio (e) is defined as the ratio of the volume of voids to the volume of solids in a soil mass. To calculate the void ratio of the given soil sample, we need to calculate the volume of solids and the volume of voids.

1. Calculation of Volume of Solids:
The volume of solids (Vs) can be calculated using the following formula:

Vs = W / G * ρw

where ρw is the density of water, which is 1000 kg/m3.

Converting the given data into SI units,

W = 0.1 kg
V = 60 * 10^-6 m3
G = 2.5

Vs = 0.1 / 2.5 * 1000

Vs = 0.04 m3

2. Calculation of Volume of Voids:
The volume of voids (Vv) can be calculated using the following formula:

Vv = V - Vs

Vv = 60 * 10^-6 - 0.04

Vv = 20 * 10^-6 m3

3. Calculation of Void Ratio:
The void ratio (e) can be calculated using the following formula:

e = Vv / Vs

e = 20 * 10^-6 / 0.04

e = 0.5

Therefore, the void ratio of the given soil sample is 0.5.

Explanation of Void Ratio

Void ratio (e) is an important parameter to determine the compressibility and shear strength of soil. It is defined as the ratio of the volume of voids to the volume of solids in a soil mass.

A soil sample consists of solid particles and voids (pores or spaces between the particles). The volume of voids is the difference between the total volume of the sample and the volume of solids. The void ratio indicates the degree of saturation of the soil and its ability to hold water.

A higher void ratio indicates that the soil has more voids and less solid particles. This means that the soil can hold more water and is more compressible. A lower void ratio indicates that the soil has less voids and more solid particles. This means that the soil can hold less water and is less compressible.

The void ratio is an important parameter for geotechnical engineers and soil scientists as it helps in predicting the behavior of soil under different loading conditions. It is also used to estimate the settlement of soil under a given load and to design foundations for structures.