GEOTECHNICAL CENTRIFUGE MODELLING TECHNIQUES FOR SUBMARINE SLIDES

The gradual shift of hydrocarbon developments into deeper waters has presented fresh challenges for offshore geotechnical engineering. Many installations in deep water require export pipelines to shore which can be many hundreds of kilometers in length. These pipelines must negotiate unstable regions of soft seabed around the steep continental shelf and variable terrain including canyons with depths ranging from tens of meters to a several hundred meters. These challenging conditions present potential geohazards for which little understanding has been developed so far. One of the major geohazards is the impact of a submarine landslide on nearby pipelines which could potentially damage the pipeline. Consequently, a Joint Industry Project (JIP) has been initiated at the Centre for Offshore Foundation Systems to improve methods for assessing the potential damage to pipelines and to provide information to assist re-routing of a pipeline to a safer alignment if necessary. This paper presents an overview of the development of specific modeling techniques to (i) trigger a submarine landslide in a geotechnical centrifuge, (ii) measure the strength properties of the slide material before, during, and after the slide failure and (iii) measure the interaction between the runout material and the seabed.