Geotechnical Data and Pile Design - Offshore Structures: Design, Construction and Maintenance - page 282

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MRBS3000 with GRLWEAP input parameters for coring - lower bound SRD
MRBS3000 with GRLWEAP input parameters for plugged - upper bound SRD

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MRBS3900 with GRLWEAP input parameters for coring - lower bound SRD

MRBS3900 with GRLWEAP input parameters for plugged - upper bound SRD

Delmag D80 with GRLWEAP input parameters for coring - lower bound SRD

Delmag D80 with GRLWEAP input parameters for plugged - upper bound SRD

0

0 50 100 150 200

Blows per 0.25 meter

250 300

FIGURE 4.16 Blowcount versus SRD curves for three hammer types for 30-inch pipe pile with
1 4 -inch wall thickness.

Depending on the pile-driving plant finally selected, it may be advisable to have
equipment readily available during piling operations in case refusal or particu-
larly high blowcounts occur at 27.2 m below the seabed. If refusal occurs, an
assessment may be needed of the effect on ultimate pile capacity and therefore
on target penetration.
The pile analysis usually assumes uniform wall thickness over the entire pile
length. Should the wall thicknesses of the piles finally selected differ from this,
then the drivability analyses should be repeated to assess the effect on blow-
counts and achievable penetration. It is recommended that consideration be