Pile Design and Construction Practice, Fifth edition

For cyclically applied loading take

In the absence of laboratory compression tests, the appropriate value of ‡cin equation 6.39
can be taken as 0.01, and the p–ycurves will be derived in the same manner as for a
normally consolidated clay.
Therefore

The deflection corresponding to pbis mm.
Other points of the p–ycurve are calculated from equation 6.38. Thus for y 15 mm:

Similarly for

y 25 mm, p 268 kN per m depth

y 50 mm, p 338 kN per m depth

y 75 mm, p 386 kN per m depth.

Beyond the critical point at 3yc, the p–ycurve decreases linearly from pb 0.72puto zero
at y 15 yc 487 mm for x/xr 0.
The p–y curve at sea-bed level for the six points established above is shown in
Figure 8.19a.
At 0.5 m below sea bed

For y 15 mm, p kN per m depth. Similarly

y 25 mm, p 280 kN per m depth

y 50 mm, p 352 kN per m depth

y 75 mm, p 403 kN per m depth.

The p–ycurve falls linearly at 15yc 487 mm to a value of
10 kN/m.
The p–ycurve for x 0.5 m is also plotted in Figure 8.19a and the curves for values of
xof 1.0, 1.5, 2.0, and 2.5 m below sea bed, established in a similar manner, are also shown
on this figure.
The value of p 421 kN/m represents the pressure at which yielding of the soil at the sea
bed occurs. Therefore

bending moment at sea- bed level Mt 26 0.421 10.9 MN m

p 0.72 610 0.522.1

610 0.5^3 15/32.5 236

pb 0.72 610 439 kN/m at y 97 mm.

pu 3.13 150 1.3 610 kN per m depth.

Nc 3 1.29.810.5

150

0.250.5

1.3

3.13

p 0.5 585 ^315

32.5

226 kN per m depth.

3 yc 3 32.5 97

yc 2.50.011.3 0.0325 m 32.5 mm

pb 0.72pu 0.72 585 421 kN per m depth

426 Piling for marine structures