When particle sizes are evenly distributed within soil, what is this classification called?

The classification of soil where particle sizes are evenly distributed is referred to as well graded. This term describes a soil that has a good range of particle sizes, which contributes to a denser arrangement and better compaction abilities. Well-graded soils have a higher amount of interlocking particles, leading to improved stability and strength, making them favorable for construction and engineering applications.

In contrast, uniformly graded soils consist mainly of particles that are similar in size, resulting in less void filling and potentially weaker structures. Gap-graded soils involve a specific range of sizes that are not evenly distributed, meaning certain sizes are absent entirely. Poorly graded soils, as the term suggests, have a limited range of particle sizes and may perform poorly in terms of drainage and structural integrity due to their inability to compact effectively. Therefore, the term well graded accurately captures the concept of even distribution of particle sizes within soil.