The Role of Expanded Polystyrene and Geocell in Enhancing the Behavior of Buried HDPE Pipes under Trench Loading Using Numerical Analyses

In recent years, much research has focused on the use of various materials for relieving and strengthening soil, e.g., steel reinforcing ribs, geosynthetics, geocell, waste tires, and expanded polystyrene (EPS). EPS is being used increasingly in geo-infrastructure, being a super-light material, to replace part of the soil and decrease the ground pressure on buried structures. This paper presents experimental and numerical analyses of the effectiveness of expanded polystyrene and geocell reinforcement for ameliorating the behavior of unpressurized buried pipes exposed to surface loading. A 3-D finite element method (FEM) model of soil, geofoam, geocell, and piping was generated in ABAQUS, and the model was verified by experimental analyses conducted at a laboratory. The results show that reinforcing the soil cover with geocell and geofoam has a substantial impact, decreasing the maximum surface settlement by around 29% and maximum pipe crown displacement by up to 39.5%. In addition, the EPS block density can reduce the maximum pipe crown displacement substantially.