As the void ratio (e) increases, what happens to density?

• A. Increases
• B. Decreases
• C. Remains the same
• D. Varies

Answer: (B)

As the void ratio (e) increases, the density of the soil decreases. The void ratio is defined as the ratio of the volume of voids (spaces between soil particles) to the volume of solids. When the void ratio increases, it means that there is a larger volume of voids relative to the volume of solids.

Density is calculated as the mass of the solid particles divided by the total volume (which includes both the volume of solids and the volume of voids). Thus, as the voids increase while the mass of solid particles remains constant, the total volume increases, leading to a lower overall density. This relationship holds true for saturated and unsaturated soils, emphasizing that an increase in voids reduces the compactness of the soil structure, resulting in decreased density.

This concept is crucial in soil mechanics, as understanding how void ratio affects density can influence many engineering applications, such as stability analysis, load-bearing capacity, and compaction efforts in construction projects.