McLaughlin Group Inc. in Greenville, SC, has added Akkerman’s Guided Boring Machine (GBM) as an accessory to its current product line.
The GBM is a trenchless installation method, offering grade and line precision required in gravity sewer and water main services. By using this pilot hole drilling technique, the contractor assures an on-grade installation with the GBM 240A jacking frame, to be followed by a conventional installation of casing using auger boring technology.
The Akkerman GBM also can be used as a stand-alone unit to install clay, concrete and steel pipe in a three-step process, and distances of up to 300 ft. The unit is powered by a separate hydraulic power pack with dual pumps to ensure maximum independent thrust and rotation.
All line and grade monitoring of the pilot hole are accomplished by means of an LED illuminated target contained in the cutter head that is visible to the operator by means of a theodolite, camera and monitor in the entry pit, with line and grade accuracies of .25 in. in 300 ft. Because of the double-walled pilot tube, liquid for cooling the cutter head and softening the soil to lessen the jacking loads required can be pumped to the face without disturbing the target.
The GBM 240A jacking frame easily mounts to the track assembly of the auger boring machines from 24- to 60-in. diameter using adapter plates, with no welding or special tools required. In addition, the jacking frame of the GBM duplicates the centerline of the boring system in order to maintain a consistent thrust point, not only for the pilot bore, but also for the casing installation which follows the same centerline.
Once the GBM has drilled the pilot hole to acceptable line and grade, the jacking frame is removed from the boring machine and a casing adapter welded to the casing and attached to the pilot tubes.