What is the depth associated with cohesionless sands and gravel?

What is the depth associated with cohesionless sands and gravel?

• A. 4 ft
• B. 6 ft
• C. 2 ft
• D. 8 ft

Answer: (B)

Cohesionless sands and gravels rely on friction, not cohesion, for their strength. In field guidance and quick-reasoning rules of thumb, a representative depth used for these frictional soils is about six feet. This depth captures typical shallow fills and deposits where sands and gravels dominate, providing a practical standard for estimating bearing capacity and evaluating soil conditions in common construction scenarios. Shorter depths may not reflect the full frictional behavior of the layer, while deeper depths often bring in different soil types or conditions, so six feet serves as the standard reference for cohesionless layers in this context.

Cohesionless sands and gravels rely on friction, not cohesion, for their strength. In field guidance and quick-reasoning rules of thumb, a representative depth used for these frictional soils is about six feet. This depth captures typical shallow fills and deposits where sands and gravels dominate, providing a practical standard for estimating bearing capacity and evaluating soil conditions in common construction scenarios. Shorter depths may not reflect the full frictional behavior of the layer, while deeper depths often bring in different soil types or conditions, so six feet serves as the standard reference for cohesionless layers in this context.