The "Deadman" is selected as an "Anchor type" in the combo list in the dialog window "New anchor".
The deadman anchor requires input of:
- Location of anchor - depth, length, spacing
- Stiffness of anchor - anchor diameter ds or area of anchor A, elasticity modulus E
- Parameters for verification of anchor (Strength of anchor, Pull-out resistance from soil is decribed below)
Deadman parameters input
The deadman consists of a bar with specified length and anchor element.
The pull out resistance from soil is equal to the passive resistance along the height of anchoring element, which is reduced by coefficient k:
For h = 0:
For h ≥ b - bD:
height of the overburden over the anchor element
width of anchor element
spacing between anchor elements
height of anchor element
depth of bottom edge of anchor element
coefficient of passive earth pressure
unit weight of soil
The coefficient k is interpolated for the intermediate values of h.
Calculation of the overburden over the anchor element:
depth of deadman
The full pull out resistance is activated if active and passive earth wedges do not intersect.
The minimum length of the bar for full pull out resistance is computed as follows:
angle of internal friction
height of shoring structure
In case that the length of bar l is shorter then minimum length of bar lmin, the passive pressure is considered from the intersection of active and passive earth wedges.
The principle of determining the minimum length for deadman´s bar