OrcaFlex Manual - Orcina

w
Inclination
Ez
End A
P0
Figure: P-y modelling
Load-deflection curves
API RP 2A Soft Clay
y
Ex
P
345
Inclination
E x
System Modelling: Data and Results, Lines
E z
P0
End B
The load-deflection formulation is based on the ultimate unit lateral bearing capacity of the soil, pu. The code
provides two equations for this:
(6.8.2-1) pu = 3c + ɣX + JcX/D
(6.8.2-2) pu = 9c
where c is the undrained shear strength, D is the pile diameter, ɣ is the effective unit weight of soil, J is a
dimensionless empirical constant and X is the depth below soil surface.
The first equation, 6.8.2-1 is meant to capture the reduced lateral bearing capacity of the soil close to the surface.
The intent of the code is that pu is defined by whichever of 6.8.2-1 and 6.8.2-2 gives a smaller value. The code
approaches this by defining XR, the depth to which the reduced resistance zone extends, and applying 6.8.2-1 for
X