Full casing barrier construction is the key to excavation, connecting casing, obstruction clearance, pipe hole backfill, to enhance the casing process.
(1) into the hole steps: the first section of the casing against the center (base section + lengthening section), and then connect the second section of the casing, so that the gravity, clamping mechanism of the rotating force and clamping mechanism pressure Under the combined effect of the first step to increase the first section of the casing bit load, began to turn the cutting, and then use the drop hammer grabbed the casing obstruction.
(2) the process: the formation of hardening site → measuring hole → full rotation of the whole tube drill in place → hoisting the first section of the casing casing → control vertical degree → press the first section of the casing → proof of vertical → underground Barrier → fill soil backfill compaction successive pull casing → full rotary drilling machine shift.
Hole backfill: the removal of obstacles, you must use the digging machine will fill the soil backfill to the casing, from the casing orifice position back to the casing, while back to fill the edge of the reverse rotation of the casing, until back to the ground. Backfill with layered tamping method, backfill 5 to 6 meters with a heavy hammer after repeated times, and then backfill, until the backfill to the ground elevation. (Filled with a contractor is responsible for the supply) casing removal using rotary device reverse rotation, removal and backfill should be carried out simultaneously to ensure that the backfill filled with holes and ensure the backfill of the dense. Extubation to the ground should be suspended when the removal, until the backfill material is completed and then remove the remaining casing. As the casing in the rotary drilling section under a section of the pressure under the long, so the removal of the casing is also carried out in accordance with the method of section by section, pull out the lower part of the casing.