Soil structure interaction of flexible pipe under pressure : Zarghamee, M S; Tigue, D B Trans Res RecN1087 1986, P46–53

Abstract

This paper contains the results of a finite element analysis of the soil-structure interaction of a buried flexible pipe subjected to internal pressure. The analysis is performed using a fine mesh so that (a) an accurate representation is made of the highly variable soil stiffness in some installations, similar to that of a pipe with poorly supported haunches resting on a hard bedding, and (b) an accurate model is made of the pipe wall stresses in light of the rapid attenuation of local deformations and strains in flexible pipe buried in stiff soils. In addition, the nonlinear behavior of pressurized flexible pipe, including large deflections and the flexural stiffening effect of the pressure-induced membrane stresses, is modeled. A special purpose program, FLEXPIPE, is developed. The program uses Duncan's soil model and considers the step-by-step nature of construction. It is used to calculate the stresses and strains in a buried flexible pipe with improper haunch support and hard bedding. It is shown that significant flexural stresses are developed at the invert of the pipe after installation and that internal pressure magnifies the flexural stresses and strains thus developed.