Hashash leads effort to create guidelines for horizontal directional drilling

By McCall Macomber, Illinois Center for Transportation

Advancements in horizontal directional drilling – a method in which a small-diameter tunnel is drilled under an area like a roadway or body of water – and lower installation costs have led to its increasing use in Illinois.

To serve this growing need, Illinois Center for Transportation and Illinois Department of Transportation (IDOT) aim to create standard guidelines in their joint project, “R27-198: Development of Guidelines for Implementation of Horizontal Directional Drilling.”

Youssef Hashash, University of Illinois Urbana-Champaign Department of Civil and Environmental Engineering William J. and Elaine F. Hall Endowed Professor, leads the project with Heather Shoup and Joseph Angeli, IDOT’s Central Bureau of Materials geotechnical engineer and District 6 permit technician, respectively.

Horizontal directional drilling can be used for smaller-scale purposes such as installing utility cables or pipelines and is quickly becoming a popular alternative to the trenching method, which involves digging or cutting up the ground.

“If every time a utility needs to build something across the right-of-way, you would have to block the road, dig it up, open a trench, lay down the pipeline or the pipe or cables, etc. (and) then close it up,” Hashash said. “(It’s) very disruptive, damaging, and just overall is not good.”

Horizontal directional drilling offers a solution to these challenges by allowing workers to go underneath the designated area to complete the work more quickly and with less impact to the environment.

Hashash, however, cautions “every new technology has its own challenges,” noting that settlement or distress can occur if horizontal directional drilling is not performed correctly.

“The crux of the problem we’re trying to deal with is how you control the installation so you can successfully put it in while having minimal impact to IDOT assets,” Hashash added.

With an increasing number of permits being sought for pipes of various materials, diameters, lengths and installation depths, creating acceptable and safe limits for these different scenarios is key.

To create guidelines for horizontal drilling, researchers took a three-step approach, beginning with observing the successes and challenges of nine horizontal directional drilling sites.

They also investigated how other states and organizations approached using horizontal directional drilling by reviewing over 400 documents on the technology, ranging from academic articles and books to industry codes and standards.

As a final step, the researchers surveyed key stakeholders in the industry on their use of the technology to discover what their challenges are and what guidance they would like to have.

Through the three-year effort, the researchers developed four proposed guidance documents for horizontal directional drilling — design and construction guidelines, guidance specifications, a permit submittal checklist and an inspector checklist.

The next steps? Fine-tune the four proposed documents and incorporate them into IDOT’s system.

Once implemented, the team expects to see savings for both IDOT as well as taxpayers.

Drivers in Illinois can also expect additional benefits from the technique: faster and safer roadways because of reducing or eliminating the need for work zones to complete this work.

“Because horizontal directional drilling is trenchless, it also reduces the time for having to do lane closures with the public and less traffic control and that increases the safety to the public as well,” Shoup said. “So, there are a lot of benefits to looking at using this technology in the broader applications.”