chapter  54
Use of the free fall cone penetrometer (FF-CPTU) in offshore landslide hazard assessment
ByJ.S. L’Heureux, M. Vanneste, A. Kopf, M. Long
Pages 6

Free Fall penetrometer (FF-CPTU) testing can provide significant advantages over conventional CPTU investigation for shallow sub-surface offshore site investigations. Much work has been done on soil characterisation and on determination of the undrained shear strength (su) from FF-CPTU testing. However, little data has been published on analysis of FF-CPTU dissipation testing. Here, FF-CPTU data from two Norwegian fjords with evidence of recent landsliding are presented, and the techniques used to analyse and correct the data are described. At Hommelvika, relatively high residual excess pore pressures (15–17 kPa) were found in the vicinity of a large pockmark identified on the fjord bed from multibeam data. At Finneidfjord, the residual excess pore pressures are lower and are in agreement with long-term piezometer data from the area. Reliable estimates of the coefficient of consolidation (ch) were also be obtained from the FF-CPTU dissipation tests.