The Behavior of a Buried Pipe Overlain by Geofoam Due to Cyclic Loading

This paper examines the ring deflection of flexible high-density polyethylene pipe caused by repetitive cyclic plate loading under various burial conditions and relative densities. It also looks at possible mitigation strategies, such as using geosynthetic materials like geofoam to lessen the effects of cyclic vehicular wheel load. Geofoam has a new post-beam arrangement where the post is the vertical support for the beam, and the horizontal capping is the beam. The influence of soil cover thickness, relative density, pipe diameter, geofoam post widths, and beam thicknesses (h) on pipe deflection was compared with the unimproved sand fill scenario. Increasing relative density and cover depth improved the pipe's ring deflection and eliminated the excessive surface settling. Further reduction of more than 60% was achieved with the protective layer of geofoam and brought the over-deflection of the pipe to an acceptable limit. An extensive parametric analysis determined the optimum burial depth and precise location of the geofoam to negate the ring deflection subjected to cyclic loading. Using commercially available finite element software (PLAXIS 3D), a new model was created and validated using experimental results and mathematical solutions derived from the modified Iowa formula. The experimental findings corroborated sufficiently with the numerical and analytical solutions.