Page 108 - Pipelines and Risers
P. 108
Soil and Pipe Interaction 81
Nc = bearing capacity factor, 5.14 for long foundations
Classic Method
I M)w ... - . . . . . . . __.__._i
0 0.02 0.04 0.06 0.08 0,l 0.12
Seabed penelmion (m)
Figure 5.2 Pressurdpenetration curve (Classic method).
5.2.3 Buoyancy Method
This method is intended for use with pipelines resting on very soft clays only. The buoyancy
method assumes that the soil has no strength and behaves like a heavy liquid. The penetration
is estimated by demanding that the soil-induced buoyancy of the pipeline is equal to the
vertical contact force.
(5.4)
where:
B= width of pipeline in contact with soil
A, = penetrated cross sectional area of pipe
0 = buoyancy
Buoyancy Method
1 Seabed penetration (m)
Fwre 5.3 Pressurdpenetration curve (Buoyancy method).
