Mechanical Behavior of Buried HDPE Pipe Subjected to Surface Load: Constitutive Modeling and Finite Element Method Simulations

Abstract

In this paper, the Sherwood–Frost constitutive model was first used to simulate the stress response and deformation process of buried high-density polyethylene (HDPE) pipe subjected to surface load, where parameters in this model were obtained by fitting the results of uniaxial tensile tests with different rates and the pipe–soil model was conducted in abaqus. Apparent stress concentration and large deformation are observed in pipe cross section and are closely related to the magnitude and location of surface load. The increments of surface load and offset displacement have opposite effects on the mechanical behavior of pipes. Additionally, the location of the maximum stress appears to shift from the top or bottom to the left and right sides of the pipe cross section with the increment of surface load, and the region of peak hoop stress will show a decreasing trend of counterclockwise rotation. Then, based on stress failure criterion, the relationship between the ultimate bearing capacity of the pipe and the offset displacement was determined, which decided by the angle between the ground and the line connecting load center and cross section center of pipe. Finally, an offset of 0.6 m is a value of interest. When the offset between the load position and the pipe exceeds 0.6 m, the ultimate bearing capacity of the pipe will increase significantly with the increase of the offset. The results of the above research could provide the reference for the safety evaluation and maintenance strategy of gas polyethylene pipe under the surface load.