Horizontal directional drilling (HDD) has been used by municipalities for pipeline installations for over 20 years. When it comes to installing larger diameter pipelines using HDD, the standard practice involves pulling a strong steel casing along the alignment, then pulling the smaller
carrier pipe(s) through the casing. The larger diameter drilling operations require a strong casing to resist vertical soils loads and protect from deflection of the carrier pipe. When the particular alignment requires horizontal or vertical curvature beyond the typical allowable bending radius
of large diameter steel, an alternative must be investigated. For this particular project, the use of high density polyethylene (HDPE) was utilized for both the casing and the carrier pipes. To enhance the vertical soils loading of the casing and pullback strength, the combination of exterior
casing and interior carriers were sized to minimize the annular space and allow the interior barrels to provide added support the casing. The project resulted in the largest diameter HDPE pipe ever installed using HDD.
Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.