Geotechnical properties of soil are very important in the geotechnical design and evaluation of the condition of the soil. Soil is a material that generally does not have consistency in its properties.
However, during the designs, we have to make sure that there is adequate consistency in the soil properties.
Otherwise, it could lead to the settlement of the foundation and lead many other issues connected with that.
The following properties are generally checked during the designs.
Grain Size Distribution
As the name implies, it is the change in the size of the soil particles.
This is also called the particle size distribution.
The grained size distribution can be obtained from the sieve analysis test. For the fine grain soils, hydrometer analysis is used to find the grain sizes.
Weight Volume Relationship
The soil contains solid partials, water and air.
When we find the relationship between the weight and volume of the soil, the void ratio is come to the action.
Void ration = v = Volume of Voids / Volume of Solid
Thus, the dry density of the soil can be specified as follows.
Dry Density
γd = Gsγw / (1 + e)
Where, γd – dry density of soil
Gs – Specific gravity of soil
γw – Density of water
Saturated Density
γsat = [Gsγw + eγw] / (1 + e)
Atterberg Limits
Atterberg limits are widely used in the soil classifications. It is kind of measure of the soil properties.
It reflects the behavior of the soil.
A soil has four main stages.
- Solid state
- Semisolid state
- Plastic state
- Semiliquid state
The moisture content of the soil is causing the soil change to above stages.
There are three limits in the Atterberg limits.
Liquid Limit (LL)
Plastic Limit (PL)
Shrinkage Limit (SL)
The difference between the liquid limit and the plastic limit is used to calculate the plastic index (PI) of the soil.
PI = LL – PL
