Buried Flexible Pipe With Nonuniform Soil Support

Abstract

The initial states of stress and deformation of a buried flexible pipe with unsupported haunches are calculated modeling the buried pipe as a cylindrical shell supported on an elastic foundation with nonuniform stiffness. The deformed pipe is then subjected to internal pressure and the changes in the states of stress and deformation are computed. The results obtained through numerical integration of the differential equations governing the nonlinear behavior of the buried pipe show that the invert of a flexible pressure pipe with unsupported haunches flattens and flexural strains develop at the invert. Furthermore, the flattening at the invert increases the hoop strain in the pipe resulting from the internal pressure. Implications of these strains on design and installation of flexible pipe are studied.