Enter the total volume of voids (Vv) and the volume of solids (Vs) into the Void Ratio Calculator. The calculator will evaluate and display the void ratio (e) and porosity (n).
- All Construction Calculators
- Porosity Calculator
- Degree of Saturation Calculator
- Bulk Density Calculator
- Specific Gravity Calculator
- Soil Stockpile Volume Calculator
- Volume Ratio Calculator
- Moisture Content Calculator
Void Ratio Formula
The following formula is used to calculate the void ratio.
e = \frac{V_v}{V_s}- Where e is the void ratio (dimensionless)
- Vv is the total volume of voids
- Vs is the volume of solids (soil particles)
To calculate the void ratio, divide the total volume of voids by the volume of solids. If you also need porosity, use n = e/(1+e) (multiply by 100 to express n as a percent).
How to Calculate Void Ratio?
The following example problems outline how to calculate Void Ratio.
Example Problem #1:
- First, determine the total volume of voids.
- The total volume of voids is given as: 40.
- Next, determine the volume of solids.
- The volume of solids is provided as: 80.
- Finally, calculate the void ratio using the equation above:
e = Vv / Vs
The values given above are inserted into the equation below and the solution is calculated:
e = 40 / 80 = 0.5
(Optional) Porosity: n = e/(1+e) = 0.5/1.5 = 0.3333 = 33.33%
FAQ
What is the significance of the void ratio in soil mechanics?
The void ratio is a critical parameter in soil mechanics because it describes how much void space exists relative to the solid particles. It is closely related to porosity and influences compressibility, permeability (drainage), and strength characteristics used in geotechnical design.
How does the void ratio affect soil compaction?
The void ratio directly impacts soil compaction. A lower void ratio means that the soil particles are closer together, which generally corresponds to a denser (more compacted) soil. This is desirable in construction projects where a stable and firm foundation is required. Conversely, a higher void ratio indicates a looser soil structure with more void space.
Can the void ratio change over time?
Yes. The void ratio can change due to processes such as consolidation under sustained load (typically decreasing void ratio), swelling/shrinkage from changes in moisture content, freeze–thaw cycles, or internal erosion/suffusion in some soils.
