Question

Effective size of a soil is ___

• A. \( D_{30} \)
• B. \( D_{60} \)
• C. \( D_{50} \)
• D. \( D_{10} \)

Hint:

When dealing with soil gradation, \( D_{30} \) is a commonly used measure for understanding soil particle size distribution.

Answer 1

The Correct Option is A

The effective size of soil is typically defined as \( D_{30} \), which is the particle size where 30% of the soil mass is finer and 70% is coarser. It represents the characteristic size of the soil particles for analyzing permeability and other properties. Hence, the correct answer is \( D_{30} \).