What is a Conical Frustum?


What is a Conical Frustum?

Diagram of a Frustum Cone

A conical frustum is an essential part of earth anchor mechanics. A basic definition of a “conical frustum” is a cone with the top sliced off.

After an earth anchor is driven to depth, tension is applied to “lock” it in place. The locking process turns the anchor 90 degrees into a horizontal orientation, and creates a frustum of compacted soil above it. This frustum is proportionally much larger than the anchor, giving the anchor its full load bearing capacity.


Photo of Earth Anchors

In some cases, the shear strength of the soil is exceeded during tensioning, causing it to fail. The solution to such failure may be using a larger anchor, which increases the volume of the frustum and thus its bearing capacity.



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