Trench Excavation Effects on Adjacent Buried Pipes: Finite Element Study

Abstract

Ground movements generated by the excavation of trenches presents some risk of damage to buried services nearby. The effects of such excavation on adjacent buried pipes have been analyzed using a three‐dimensional finite element model having elastic material properties. The bending moments and displacements induced only in pipes running parallel to open, unsupported, rectangular trenches have been considered. The results show that small diameter pipes, such as those having diameters and longitudinal bending stiffnesses smaller than those for a 6 in. diameter cast iron pipe, closely follow the movements of the ground and that, for practical purposes, the moments induced in such pipes may be assumed to be directly proportional to their flexural rigidities and inversely proportional to the elastic modulus of the soil. These proportionalities break down for large diameter pipes which are less flexible and restrain the ground from moving freely. The ground movements and pipe‐strains predicted by the analysis have been found to be of the same order as those measured in several field tests.