Pushing the Limits When Does It Make Sense to Attempt a Longer and Larger HDD Installation

Author(s): G. Duyvestyn, M. Gelinas
North American Society for Trenchless Technology (NASTT) NASTT’s 2015 No-Dig Show

Abstract

Horizontal directional drilling (HDD) methods are being used to install longer and larger diameter installations and in areas once thought impossible for this method, with the energy sector primarily driving the need for more challenging installations than what have been completed in the past. Technological advancements and innovative approaches within the HDD community are driving the application of the HDD method to new and unchartered areas. In the past, most of the industry advancements have been completed through a contractor proposed value engineering process with a shared cost savings approach.

Today there is an industry pressure to pursue longer and/or larger installations and within difficult ground conditions that present a greater number of challenges/risk factors than in previous installations. When installation limits are being advanced, design and contractual countermeasures need to be fully established and in place to deal with the potential risks that may occur when advancing technological capability. The difficulty lies in balancing the risks associated with pushing a technology limit and how big of a step should be considered. This paper examines the current limits of the HDD industry, discusses typical geotechnical and installation specific risks, and presents a framework that focuses on identifying, characterizing, and managing installation risks to allow for proper evaluation of the complete risk profile for a particular long length, large diameter, and challenging HDD crossing.