Pile driveability in low- to medium-density chalk

Pile driving in low- to medium-density chalk is subject significant uncertainty. Predictions of “chalk resistance driving” (CRD) often vary considerably from field behaviour, with both pile refusals and free falls under zero load being reported. However, recent studies have led better understanding the processes that control wide range behaviour seen field. This paper describes primary outcomes analysis dynamic tests at an onshore offshore site uses results propose a new method predict CRD. The based on phenomena identified experimentally: relationship between cone penetration CRD, attenuation local stresses as advances, operational effective stress interface shear failure characteristics. proposed evaluated through back-analyses records independent installation cases were not included developing method, but involved known ground conditions, hammer characteristics, applied energies. shown lead more reliable predictions CRD than approaches currently by industry.