Simplified Methodology for Selecting Polyethylene Pipe for Mini (or Midi) — HDD Applications

A simplified methodology is presented to estimate the required pull loads on polyethylene pipe installed by a mini (or midi) — HDD process. A simplified procedure is also presented to evaluate the potential collapse tendency of the PE pipe during the installation or post-installation phases. The methodology and associated formulae are based upon approximations to the more complex set of equations and procedures provided in ASTM F 1962, Standard Guide for Use of Maxi-Horizontal Directional Drilling for Placement of Polyethylene Pipe or Conduit Under Obstacles, Including River Crossings. The objective is to provide a convenient means of identifying potentially problematic mini-HDD installations and/or to aid in the pipe (DR) selection process, in contrast to the extensive planning or analytical investigations characteristic of typical maxi-HDD projects. The proposed mathematical model reflects the major route parameters (bore length, planned bends) and buoyant weight for an empty PE pipe, and also accounts for unplanned curvatures (undulations) resulting from path corrections in a typical mini-HDD installation.