Analysis of polyethylene pipe behaviour in horizontal directional drilling field tests

The paper presents results of both tests and analysis of polyethylene pipes installed using horizontal directional drilling (HDD). A total of seven full-scale HDD field installations were performed at the University of Waterloo. The test parameters were pull length, overcut ratio, quality of the drilling fluid, pipe diameter, and pipe material. The paper presents an overview of the testing methodology, instrumentation, and test specimens. The method for measuring strains along the length of the pipe is presented and discussed. Experimental results concentrate on pipe strains due to bending and axial deformations during HDD. Post-installation axial strains are also presented. A predictive model has been developed to analyze the pipe under various installation conditions. The model accounts for major mechanical contributions to the pulling force in HDD installations. The emphasis in this paper is on the comparison between theoretical and experimental results and the discussion of factors influencing pulling loads and strains in polyethylene pipes installed using HDD.