Parametric Studies of Reducing Applied Stress on Buried Pvc Pipes Using Finite Element

Abstract

The buried pipes are used for many purposes as drainage and water supply in addition many other projects such as oil pipelines and transferring the rivers water. The used pipes are made from various materials and different diameters which are mostly subjected to moving stresss and overburden pressures. The present study is focused on possibility of reducing the effect of applied stress on the buried PVC pipes into the loose and dense conditions of sand soil by reducing the settlement of using geogrids and thin layer of concrete. The response of the pipes was studied with and without treatment. In this study, finite element analyses were used to evaluate the behaviour of 500 mm PVC pipe buried in sand soil. The effects of many variable parameters as embedment ratio of pipes, density of soil and geogrids locations were investigated. Twenty-two models were conducted using Plaxis 3D program.ّ Dimensionsّ ofّ theّ numericalّ modelsّ wereّ )1ّ ×ّ 2ّ ×ّ 3(m.ّ Accumulated incremental stresss were applied on the surface of soil with 500 mm in width and along the length of pipe. For each model, the relationship between the surface pressure and the corresponding pipe crown deflection was investigated. In view of the results, it can be concluded that the embedment ratio of pipes, density of sand and utilizing the geogrids are fundamental parameters that influence the buried pipes. Also the results demonstrate that replacing the top soil with dense and reinforcing it by geogrid layer gives greater protection for pipes.