Correct Cleaning Method Of DTH Hammer Drill Pipe

Abstract:  When cleaning the DTH hammer drill pipe, it is first necessary to understand the cause of the sediment at the bottom o...

  When cleaning the DTH hammer drill pipe, it is first necessary to understand the cause of the sediment at the bottom of the hole.

  1. DTH hammer remains between the teeth and the bottom cover of the drill bucket.

  2. The bottom cover is not closed tightly.

  3. When drilling into the silt, sand, and flow-plastic formations, the drilling slag in the drilling bucket is seriously lost during lifting, and sometimes even all of it is lost in the drilling hole.

  4. The soil cut by the outer edge of the DTH hammer drill bucket remains on the edge of the hole bottom because the bottom of the hole is flat and cannot enter the entrance of the cylinder.

  5. The teeth of the drill bucket are arranged sparsely, and leakage between teeth is inevitable.

  6. The footage of the drilling bucket is too large, the loading is too full, and the muck is squeezed out from the drainage hole of the top cover.

  According to the characteristics of the DTH hammer method, we have developed two hole cleaning methods and achieved good results.

  At the same time, we can also control the sedimentation speed of the soil residue by changing the specific gravity difference between the soil residue and the mud and increasing or decreasing the viscosity of the mud. , we can reduce the specific gravity and viscosity to speed up the settling speed of DTH hammer slag.

  What to do if the sediment at the bottom of the hole cannot reach the standard? For this reason, we must clean the hole, otherwise, the settlement of the pile top will be large and the bearing limit value will be reduced. The common methods of DTH hammer cleaning are the settlement method and the replacement method. The so-called settlement method is the final hole. Finally, clean the hole after the soil residue settles to the bottom of the hole, and the replacement method is to clean the bottom of the hole immediately after the hole is finalized, that is, use the newly prepared mud to clean the mud in the hole before the soil residue has been deposited from the mud. A method of displacement outside the hole.

  For positive and negative circulation drilling, it is suitable to use slurry change to clear the hole, because it can use its own DTH hammer drill pipe for positive and negative circulation slurry change, while the drill pipe for rotary drilling does not have the function of conveying circulating fluid. This method needs to reconfigure the drill pipe and the corresponding DTH hammer equipment, which is not feasible, and the settlement method is commonly used the duct suction dredging pump method, the airlift method, and the submersible mud pump method.

  These methods also have some problems in use, mainly the scope of influence of the slag suction port. When the hole diameter is 1.5 meters, if the position of the slag suction port cannot be moved or there is no tool stirring at the bottom of the hole, the drilling slag far away from the radius is relatively small. Difficult to remove.