Horizontal Directional Drilling: Utility and Pipeline Applications

Determining the loads and stresses that the product pipe will experience as a result of installation by HDD is an important process and a primary concern for the owners and engineers of the pipeline system. HDD contractors, on the other hand, are usually concerned about the loads and stresses on the drilling equipment. It is common for owners and engineers who are unfamiliar with HDD design and construction methods to rely solely on the advice of the contractor as to whether a crossing is feasible. Most HDD contractors will determine that a crossing is feasible if they can successfully bore and ream the hole and pull the product pipe back through within the specified tolerances and will not consider the pipe itself. As a result, in some HDD crossings, the product pipe did not perform as intended. It is not that the HDD contractors intentionally mislead; it is just that they usually look at the crossing from a different perspective. This is the reason why it is important for the owners and/or engineers to ensure that the HDD contractor is provided with a crossing design that is acceptable for the product pipe.
Due to the relatively recent introduction of HDD construction there is not a lot of literature on the subject of product-pipe installation loads and stresses. However, this is changing as the industry grows. A detailed manual was published in 1995 by the Pipeline Research Council International [1]. This manual, which will be referred to...