NUMERICAL MODELING OF UPLIFT RESISTANCE OF BURIED CONCRETE DUCTS & PIPES

This paper presents simulation of the pipe and soil system behavior during uplift displacement of pipelines in dense and loose sand by a 2D Finite Element modelling. As the first part of an ongoing research, this study focuses on the type of the soil failure mechanism which occurs in saturated condition at different burial depths and soil densities for constant pipe diameter. Then, at this stage, pipe is considered as a linear elastic but very stiff material (compare to the soil). Using conventional continuum elements for the soil, its material behavior is modelled by the Drucker-Prager criterion. The numerical results compared to the laboratory observations and results as well as theoretical aspects. Different laboratory failure mechanisms in loose and dense soils and also loaddisplacement curves impressively reproduced by the numerical modellings. Even, development of a gap below the pipeline in dense sand well captured by the FEM results. The essential effect of the soil density on the resistance force against uplift displacement is also well illustrated by the numerical results. To obtain a normalized upheaval load-displacement curve for this phenomenon, displacements were nomalised by the pipe diameter and also burial depth, however, another more suitable length parameter is under investigation.

Keywords:

buried pipeline , uplift , sand , numerical modeling , FEM