Excess pore pressure redistribution beneath pipelines: FEA investigation and effects on axial pipe-soil interaction

摘要

Thermal expansion of seabed pipelinesmay generate excess pore pressure in the surrounding soil.This paper discusses aspects of the excess pore pressure redistribution process and their effects on the effectivestresses at pipe-soil interface, and the resulting soil resistance to pipeline axial movement. The discussion issupported by results of finite element analyses using coupled soil models, which allow pore pressure generation,redistribution and dissipation. A first model provides insight into the two-dimensionality of the redistributionprocess, illustrating why dissipation rates differ from one-dimensional consolidation processes.A second modelis used to addresses the effect of (apparent) over-consolidation local to the pipe-soil interface. This provides aplausible explanation for the observation in model tests of positive excess pore pressure in initially dilatant soilat the pipe interface.