L51697 Obstacle Detection to Facilitate Horizontal Directional Drilling

The horizontal directional drilling (HDD) technique is specially suited for pipeline crossings of waterways, beaches, roads, vulnerable natural regions, railroads and airports. The HDD method is a two-stage process consisting of navigating a drill stem underground along a predetermined design route and the pulling back of the product pipe through the prepared hole. One of the major problems faced in HDD projects is subsurface exploration and locating of existing underground obstacles. HDD equipment must avoid these obstacles if at all possible. This study was conducted to: 1. Determine the state-of-the-art for obstacle detection in horizontal directional drilling technology. 2. Examine all possible techniques for obstacle detection. 3. Evaluate the most promising and suitable techniques for further development. 4. Determine further work necessary to reach a 100-foot (30 m) target. 5. Make recommendations for HDD contractors.