What is considered a disadvantage of a crushed stone or gravel ringwall?

• A. It is not suitable for tank foundations
• B. It is difficult to construct to close tolerance
• C. It cannot support heavy loads
• D. It easily shifts under pressure

Answer: (B)

A crushed stone or gravel ringwall is often used as a foundation for tanks due to its drainage properties and ability to distribute loads. However, a significant disadvantage of using this type of foundation is that it is difficult to construct to close tolerances. This means that achieving precise levelness and alignment can be challenging.

In tank construction, maintaining close tolerances is crucial because it ensures that the tank is stable, minimizes potential for uneven settlement, and supports proper loading. Variations in the height and level of a gravel or crushed stone foundation can lead to structural issues and can affect the tank’s overall integrity. Therefore, the difficulty in achieving precise construction is a valid concern when considering crushed stone or gravel for foundation walls.