Mechanical response analysis of the buried pipeline due to adjacent foundation pit excavation

Abstract

Foundation pit is one of the most factors that threaten the safe operations of buried pipeline. In order to study the effect of foundation pit excavation on the buried pipeline, a three-dimensional model of pipeline and foundation pit was established, and the variation regulations of pipeline’s deformation under the foundation pit excavation were investigated. Effects of pipeline parameters, foundation pit parameters, soil parameters and underground continuous wall on the stress, strain and deformation of the pipeline were studied. The results show that the underground continuous wall can effectively reduce the pipeline deformation. After the foundation pit excavation, the upper surface of the pipeline’s middle section is pressed, and the lower surface is pulled, but the strain distribution of the pipeline at the edge of the pit is opposite. Horizontal and vertical displacements occurs on the pipeline, horizontal displacement moves to the inside of the pit, and vertical displacement moves to the bottom of the pit. The pipeline deformation decreases with the increasing of pipeline’s radius-thickness ratio, but it increases with the increasing of the distance between the pipeline and foundation pit. The internal pressure has a small effect on the pipeline deformation. Pipeline deformation increases with increasing of the foundation pit’s width and depth. However, the length of the foundation pit has no effect on the pipeline. The pipeline deformation increases with the soil’s Poisson’s ratio increases, and it decreases with the increasing of soil’s cohesion and elastic modulus. With the increasing of thickness and elastic modulus of the underground continuous wall, the pipeline deformation decreases. Those results can be used for pipeline laying, construction, maintenance and safety evaluation.