Calculating Total Density, Dry Density, Degree of Saturation, and Saturated Density in Clay Sample
How to determine the total density, dry density, degree of saturation, and saturated density of an undisturbed clay sample?
In order to determine the total density, dry density, degree of saturation, and saturated density of an undisturbed clay sample, we need to consider the void ratio, water content, and specific gravity of the soil. Given the following data:
- Void ratio (e): 0.75
- Water content (W): 36%
- Specific gravity (G): 2.65
Let's break down the calculation for each parameter:
- a) Total density (pcf):
- b) Dry density (pcf):
- c) Degree of saturation:
- d) Saturated density (pcf):
The total density is calculated using the formula: ρt = G ρw, where G is the specific gravity of soil solids and ρw is the density of water. Given the values, ρt = 2.65 × 62.4 = 165.36 pcf. Therefore, the total density is 165.36 pcf.
The dry density can be determined using the formula: γd = (1 + e) / G ρw. By substituting the values, we get γd = 70.2 pcf.
The degree of saturation is defined as: S = W / (G s e), which results in a degree of saturation of 0.181 or 18.1%.
The saturated density is calculated using the formula: γsat = (G s / (1 + e)) γw. Plugging in the values, we get γsat = 94.91 pcf.
Understanding the Calculations:
Total Density (ρt): The total density is the mass of soil per unit volume, taking into account the specific gravity of the soil solids.
Dry Density (γd): The dry density represents the density of soil particles without considering the presence of water.
Degree of Saturation: This parameter indicates the level of saturation of water in the soil mass, expressed as a percentage.
Saturated Density (γsat): The saturated density refers to the density of the soil when fully saturated with water.
By calculating these parameters, engineers and geotechnical professionals can gain valuable insights into the characteristics of the soil sample, which is crucial for various construction and infrastructure projects.