Spudcan Foundations on Multi-Layered Soils with Interbedded Sand and Stiff Clay Layers

摘要

The ‘spudcan’ foundations for mobile drilling rigs continue to exhibit ahigh failure rate in the offshore oil and gas industry. Contributing tothis is the more frequent use of larger jack-ups in regions with highlystratified seabeds and continual exploration in deeper and untestedenvironments. This paper reports centrifuge modelling of spudcanfoundations penetrating through multi-layered soils with interbeddedstronger layers. The soil conditions tested simulate offshore strengthprofiles that have reported punch-through failures. The effect of soiltype (and hence drainage conditions) in the critical strong layer on thelikelihood of punch-through is discussed. The experimental resultsshow that the failure was less severe for a carbonate sand layersandwiched by soft clay layer compared to that for a silica sand layer,in spite of the higher critical state friction angle of the carbonate sand.