Experimental and numerical investigation of the effect of PET waste reinforced soil fills on buried pipe behavior

To ensure the long-term and trouble-free operation of buried pipelines, surface loads must be limited. In this study, the performance of sand soils reinforced with different proportions of Polyethylene Terephthalate (PET) wastes was investigated in order to reduce the pressure transferred to the pipes under surface loads. The sand soil was reinforced with PET at the rates of 1%, 3% and 5% and the shear strength was determined. The soil layers between a square-shaped model foundation and the buried pipe were reinforced with PET wastes at the specified rates and experiments were carried out under static loads. The bearing capacity, settlement and stresses on the pipe were compared in reinforced and unreinforced soils, and the performance effects of the reinforcement location and thickness were evaluated. The results showed that the soil bearing capacity increased by up to 217% with PET reinforcement, while the stresses in the pipe reduced by up to 86%. Moreover, as the thickness of the PET-reinforced layer increased, the bearing capacity improved, and the stresses acting on the pipe decreased. The highest bearing capacity was achieved with 3% PET reinforcement, while the lowest pipe stresses were observed with 5% PET reinforcement. The reinforcement method under the foundation was found to be more effective than reinforcement above the pipe. This study demonstrates that using PET waste as a soil reinforcement material to reduce the loads acting on buried pipes offers both environmental and engineering benefits.