Shear Strength of Skin
For each segment of the analyzed pile the program determines the limiting value of the force that can be transmitted by the pile skin at the location of a given segment. Its value depends on the geostatic stress σz found at a depth of a given segment.
where: | γ | - | unit weight of soil |
h | - | depth below the ground surface |
Summation sign denotes that σz is summed over individual layers of the soil.
The allowable shear stress is then given by:
where: | c | - | cohesion of soil at the location of the beam |
φ | - | angle of internal friction of soil at the location of the beam | |
k | - | coefficient of increase of allowable skin friction due to technology |
If the beam is found below the groundwater table, the allowable skin friction is then reduced to receive the form:
where: | u | - | pore pressure below the groundwater table |
The allowable shear force then follows from:
where: | O | - | length of the perimeter of the pile skin |
l | - | length of the pile beam |