Parametric study examining the short and long term response of HDPE pipes when installed by horizontal directional drilling

Estimation of the pulling forces is an important step in the successful design of a horizontal directional drilling installation. Estimation of axial stress distribution along the pipe is also important for the prediction of its long term performance. This paper presents the results of a parametric investigation of the effect of different installation parameters on the short and long term response of the new pipe. The investigation was carried out using procedure HDDPIPE developed by the authors for the analysis of polymer and steel pipes installed by horizontal directional drilling. The results show that stresses and strains continue to change along the pipe throughout its service life. Some installation parameters have significant effects on the short term installation loads, as well as the long term axial stresses and, potentially influence expected service life. The study demonstrates that half of the maximum short term axial stress during installation can be used as a conservative measure of long term axial stress. Less conservative estimates can be obtained using the authors’ new calculation procedure.