ABSTRACT
The trenchless installation of underground utilities by horizontal directional drilling (HDD) presents several new challenges to both design engineers and owners. The objective of this paper is to add to the level of knowledge that can be applied to the use of HDD for trenchless pipeline installation. This paper presents a compilation of “lessons learned” from various telecommunications HDD projects in the City of Santa Clara, California, USA. All of these lessons are directly applicable to both conduit and pipeline installations. The paper begins with a brief description of HDD equipment and applications as well as limitations of HDD for pipeline and conduit installation. The introduction is followed by a discussion of design criteria for HDD as well as a discussion of required geotechnical information. The design and geotechnical discussions are followed by a compilation of case history examples of lessons learned on recent HDD projects.
