For example, the maximum thrust applied may be different from one cutting tool to the next. For efficient and effective drilling the machine parameters are adjusted in part based on the specific cutting tool attached to the drill string. The cutting tools have different properties and require that the machine be operated differently. The level of direct operator interaction with the drill string, such as is required to disconnect drill rods at the exit location of the borehole, is much greater than that associated with traditional horizontal directional drilling techniques.įor boring, the drill is fitted with different tools (also referred interchangeably herein as bits, cutting tool, drill attachments, boring tools) depending on the underground conditions and the particular type of hole to be drilled. A push reaming technique is sometimes used because it advantageously provides for the recycling of the drilling fluid. The reamer is then pushed through the borehole while the drill rods being advanced out of the exit side of the borehole are individually disconnected at the exit location of the borehole. It is common to attach a utility line or other conduit to the reaming tool so that it is dragged through the borehole along with the reamer.Īnother technique associated with horizontal directional drilling, often referred to as push reaming, involves attaching a reamer to the drill string at the entry side of a borehole after the boring tool has exited at the exit side of the borehole. A reamer is then attached to the drill string which is pulled back through the borehole, thus reaming out the borehole to a larger diameter. After the desired length of borehole has been obtained, the tool is then directed upwards to break through to the earth's surface. After the boring tool reaches a desired depth, the tool is then directed along a substantially horizontal path to create a horizontal borehole. A drilling fluid is typically flowed through the drill string, over the boring tool, and back up the borehole in order to remove cuttings and dirt. In accordance with such a general horizontal boring technique, also known as horizontal directional drilling (HDD) or trenchless underground boring, a boring system is situated on the ground surface and drills a hole into the ground at an oblique angle with respect to the ground surface. The general technique of boring a horizontal underground hole has recently been developed in order to overcome the disadvantages described above, as well as others unaddressed when employing conventional trenching techniques. Also, an open trench poses a danger of injury to workers and passersby. Further, there is a high probability that digging a trench may damage previously buried utilities, and that structures or roadways disturbed by digging the trench are rarely restored to their original condition. In areas supporting existing construction, a trench can cause serious disturbance to structures or roadways. Although useful in areas of new construction, the burial of utilities in a trench has certain disadvantages. In many situations, the underground utilities can be buried in a trench which is then back-filled. Utility lines for water, electricity, gas, telephone, and cable television are often run underground. The present invention relates generally to the field of underground boring and, more particularly, to a system and method for horizontal directional drilling with a boring tool library. § 119(e), and which is incorporated herein by reference in its entirety. 18, 2008, to which Applicant claims priority under 35 U.S.C. 8,499,855, which claims the benefit of Provisional Patent Application Ser. This application is a continuation of U.S.
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