| 摘要 |
<p>APPARATUS AND PROCESS FOR DRILLING UNDERGROUND ARCUATE PATHS UTILIZING DIRECTIONAL DRILL AND FOLLOWING LINER A motor-powered directional drill is advanced in an inverted arcuate path underneath an obstacle such as a water course. A second concentric and larger lining pipe follows the advance of the directional drill either simultaneously but preferably sequentially to form a concentric annulus about the directional drill. This lining pipe preserves the directional drilling path made and prevents the collapse or the erosion of the hole due to manipulation of the directional drill. When the inverted path underneath the obstacle is completed and the liner extends the full length, the liner becomes a large diameter pipe of improved tortional capability which can be used subsequently to ream the hole to full size for placement of a production casing. A specialized drilling rig is provided having one advancing chuck for crowding the directional drill into the ground and another larger rotating chuck to rotate and advance the following lining pipe into the ground concentrically about the directional drill.</p> |
