Geosynthetic Protection for Buried Pipes Subjected to Surface Surcharge Loads

Geosynthetics have been extensively used as reinforcement in several geotechnical engineering applications. Regarding pressurised buried pipes, geosynthetics can protect the pipe against mechanical damages and reduce the consequences of explosions and leakages. This paper presents and discusses the use of geosynthetic reinforcement for the protection of buried pipes against the influence of localized surcharges on the ground surface. Model tests were carried out under plane-strain conditions where increasing surcharge pressures were applied on the surface of a dense sand layer containing a buried pipe. Three polymeric geogrids were used as reinforcements. Reinforcement arrangements consisting of a geogrid horizontal layer, an inverted U arrangement and an arrangement where the geogrid completely enveloped the pipe were tested. The results obtained showed that the presence of the reinforcement was effective in reducing the vertical stresses transferred to the pipe as well as in reducing pipe strains. The arrangement with the geogrid enveloping the pipe was the most efficient and the geogrid that combined satisfactory tensile stiffness and aperture to soil particle diameter ratio was the one which performed best. The testing programme showed the potentials for the use of geosynthetic reinforcement in reducing the effects of surface surcharges on buried pipes.