Analysis of Influence Factors on Borehole Path Control Associated with Horizontal Directional Drilling

Control of the borehole path is very important in Horizontal Directional Drilling (HDD), a widely employed method for the trenchless installation of pipelines. The main factors influencing the path control are analyzed in this paper, including the angle and area of the drilling bit guide plate, the soil properties, elastic bending & anamorphic characteristics of the drill pipe, size of drilling tools with fore thick diameter and the advance rate of the drilling bit. The effect of soil properties on path control was analyzed by means of laboratory tests. The results indicated that greater borehole path deviations occurred while drilling in harder formations. Three-dimensional computer simulations were performed, including visualization of stratum, underground utilities, manholes and the horizontal borehole path. The results of the study allow improved design of the pilot borehole, consistent with soil properties, location of underground utilities and drilling equipment characteristics.