Page 107 - Pipelines and Risers
P. 107
80 Chapter 5
where:
z = seabed penetration (m)
S = F, /(D-s,)
G = s, l(D.7’)
F,= vertical contact force (kN/m)
D = pipeline external diameter (m)
su = undrained shear strength (Wa)
y‘= submerged soil density (kN/m3)
I Verley and Lund Method
Figure 5.1 Pressurelpenetration curve (Verley and Lund).
The Verley and Lund formulation is based on curve fitting to data with S . < 2.5.
For larger values the method overestimates penetration. An alternative formulation (linear),
said to be valid for all values of S . is given by:
4 = 0.09. (s . (5.2)
D
5.2.2 Classical Method
The classical bearing capacity formulation was originally based on a rectangular foundation.
The penetration normalized with pipe diameter is solved from the following equations:
(5.3)
where:
