The primary aim of this paper is to determine penetration and uplift resistances of two interfering pipelines buried in clay with a linear increase in strength. The advanced finite element limit analysis of upper and lower bound theorems is used to perform new limit analysis solutions for both penetration and uplift resistances of two interfering pipelines. The strength profiles of cohesive soils are the cases of normally consolidated clays in deep water by setting the shear strength at the ground surface to be zero and linearly increased with the depth. The twin pipelines have the same geometries and are simultaneously failed at the same magnitude of the failure uplift or bearing loads. There are three considered input parameters including the spacing between the pipes, the embedded depth of the pipes, and the unit weight of soils. All input parameters have significant influences on the penetration and uplift resistances of two interfering pipelines. Failure mechanisms of the problems are also investigated, and stability charts of the penetration and uplift resistances of two interfering pipelines are produced for practical uses in offshore geotechnical engineering.
Undrained stability of a spherical cavity in cohesive soils using finite element limit analysis
