Protecting buried pipelines using different shapes of geofoam blocks

Purpose. This research presents experimental modeling and numerical analysis on reducing stress and protecting buried pipelines using three arrangements techniques of expanded polystyrene (EPS) geofoam blocks: embankment, EPS block embracing the upper part of the pipe and EPS blocks as two posts and a beam. Methods. An experimental model consisted of steel tank with boundaries dimensions depending on the diameter of the pipe located at the center of it. The backfill on the pipe was made from sand and embedded EPS blocks with two techniques: EPS block embracing the upper part of the pipe and EPS blocks form two posts and a beam. Series of experiments were carried out using static loading on rigid steel plate to measure the pipe deformations and strains, as well as backfill surface displacement. The numerical analysis was used to simulate the experimental model using the finite element software program PLAXIS-3D. Findings. The results reveal that the most effective method which prevents stress on the buried flexible pipe was EPS post and beam system followed by EPS embracing the upper part of the pipe. The results obtained from the numerical analysis and the experiment demonstrate the same trend. The parametric study shows that EPS post and beam blocks model has higher surface displacement than embracing the upper part of the pipe model, which is more effective in case of high rigidity of the pipe. Originality. Reducing stress on buried pipes using different geofoam shapes to find which one is the optimum method. Practical implications. Two configurations of EPS geofoam blocks – EPS block embracing the upper part of the pipe and EPS blocks post and beam system - ensure successful stress reduction and protect buried pipes