What effect does an increase in void ratio (e) have on permeability?

• A. Increases
• B. Decreases
• C. Remains the same
• D. Completely stops

Answer: (B)

An increase in void ratio indicates that there is a greater volume of voids or spaces between the solid particles in a soil sample. This increase generally suggests that there is more room for water to flow through the soil. However, while one might think that more voids mean greater permeability, the relationship is more nuanced.

As the void ratio increases, the overall connectivity of soil pores can change. In some cases, if the soil becomes too loose and disaggregated, the paths for water flow may become less efficient, leading to decreased permeability. Additionally, if the larger void spaces are not well interconnected, water may find it harder to navigate through the soil mass, further reducing the ease of flow. It's important to consider the type of soil and its structure when assessing how changes in void ratio affect permeability.

Therefore, the option indicating that an increase in void ratio decreases permeability aligns with these considerations, reflecting the complex nature of soil structure and flow behavior.