A deadman anchor is a buried transverse beam, plate or bundle that acts as an anchor for a tension connection, typically used for sheet pile walls, quay walls or pile structures. The name reflects the passive behaviour: the anchor “does nothing” until a tensile force is applied through the tie rod.
How it works
A deadman anchor consists of a heavy element (concrete, timber or steel) buried horizontally or at an angle in the ground. A tie rod connects this element to the structure being anchored:
- Passive resistance — the soil in front of the anchor must be displaced before it can move
- Earth pressure — deeper and heavier soil provides greater holding capacity
- Tension connection — the rod transfers force from the structure to the anchor
Applications
Deadman anchors are common in hydraulic and earthworks engineering:
- Sheet pile walls — an anchor behind the wall prevents it from tilting forward
- Quay walls — tying back to the landward side
- Slope retention — at river banks and garden retaining walls
- Temporary excavations — supporting struts or walings
Key considerations
- Sufficient distance — the anchor must lie outside the active sliding zone of the wall
- Deep enough — above the waterline and below the frost line
- Protect the tie rod — against corrosion and soil settlement
- Calculation — passive earth resistance determines the capacity
Related terms
- Sheet pile wall
- Ground anchor
- Earth retaining structure
- Tie rod
- Grout anchor
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