Analytical Solution for Deformation Characteristics of Buried High-Density Polyethylene Pipes Considering Temperature Variations

Abstract

Buried high-density polyethylene (HDPE) pipes are widely used in solid waste landfills, heap-leach mining pads, large earth dams, and other infrastructures. Large earth pressures and elevated temperatures in these applications can lead to the failure of HDPE pipes, resulting in pipes plugged in the drainage system and increases in the leachate level. High leachate levels contribute to landslides in landfills. Based on the theory of elasticity, a plane strain pipe-soil interaction model was developed to investigate the deformation characteristics of HDPE pipes while considering the influence of temperature. Analytical solutions were obtained under perfectly smooth and fully bonded interfaces. The solutions and calculated results were verified using the Höeg formula and the results of laboratory tests. The results show that the Höeg formula is applicable to pipes with a standard dimension ratio (SDR = nominal diameter/wall thickness) greater than 40. In contrast, the analytical solutions obtained in this paper are relatively accurate for calculating the deformation characteristics of pipes when the SDR of the pipes is less than 40, as in the case of most landfills. A parametric analysis was conducted, and implications for landfills were analyzed. Furthermore, simplified equations were derived for landfill design, and preliminary suggestions were provided regarding the waste height control and temperature regulations in landfill operations. To ensure the safety and stability of HDPE pipes and to avoid environmental damage, the maximum waste temperature of the landfill should be regulated under a certain waste height, and the waste height should be controlled against a given maximum waste temperature. According to the simplified equations, the security of the drainage system can be evaluated with monitored waste height and temperature, and pipes plugged in the drainage system could be avoided.