Experimental investigation of buried flexible HDPE pipe

Abstract

Buried pipes are used mainly for water supply and drainage, among many other applications such as oil, liquefied natural gas, coal slurries, and mine tailings. The pipes used may be rigid (reinforced concrete, vitrified clay, and ductile iron) or flexible (steel, UPVC, aluminum, fiberglass, and high-density polyethylene), although the distinction between them is blurring. Deflection or buckling determines the design of flexible pipes. HDPE pipes are preferred due to their light weight, long term chemical stability and cost efficiency. This project aims to design and fabricate an experimental setup of the model trench as a steel tank filled with the desired type of soil and flexible pipe with the required depth and loading provisions to simulate uniform loading and record the behavior, i.e., deflection of the flexible plastic pipe, compare the observation with the theoretical results, and infer the findings. The deflection characteristics were to be measured with the help of a dial gauge fixed inside the pipe. Additionally, the objective is to study the load deformation behavior of the buried pipe and stress variation across the cross section of the pipe under static loading, along with the influence of depth of embedment and density of backfill on the deformation and stresses in the pipe and the deformation behavior of the buried pipe when soil is reinforced with geogrid reinforcement, and evaluate the structural performance of the pipe. Based on the conclusions, various recommendations can be made in terms of the application of buried flexible HDPE pipes in place of conventional pipes and thereby reducing the risk of leakage and damage and also compensating the cost of pipe systems economically.