Solving a Puzzling Project

摘要

Drill a pilot hole; enlarge the bore hole by backreaming as necessary; prepare product for pull-in at the exit end; pull it back through the pilot hole - the basic steps of a horizontal directional drilling (HDD) installation. But what if there is no place to lay out and prepare the product for pull-in? That was the problem faced by Pacific Gas & Electric (PG&E) for a portion of the company's L-109 pipe replacement program in an area near Redwood City, Ca., where construction was subject to strict environmental restrictions, limited work space and a short, six-month window to complete.