Soil Gradation Terminology – Name for soils with particles of nearly the same size Select the correct gradation description.

Introduction / Context:
Particle-size distribution influences density, permeability, and strength. When most particles have nearly the same size, the gradation term indicates a narrow distribution, which bears on compaction and drainage behavior.

Given Data / Assumptions:

• Soil with narrow band of particle sizes (little spread across sieves).
• Standard geotechnical terminology.

Concept / Approach:

“Uniformly graded” describes soils whose grains are nearly the same size. Such soils are also “poorly graded,” a broader class that includes uniform and gap-graded distributions. However, the most precise term for nearly same size is “uniformly graded.”

Step-by-Step Solution:

Verification / Alternative check:

Uniform soils show low coefficients of uniformity (Cu) and curvature (Cc) values indicating lack of wide size spread.

Why Other Options Are Wrong:

Well graded implies a wide, continuous distribution. Poorly graded is technically correct but less specific; gap graded indicates missing intermediate sizes.

Common Pitfalls:

Equating “poorly graded” exclusively with uniform; while related, “uniform” is the exact descriptor for near single-size soils.

Final Answer:

Uniformly graded