After correctly selecting the type of high air pressure dth hammer according to the physical and mechanical properties of the rock, the following technical measures must be taken to obtain good technical and economic indicators.

(1) According to the rock formation, the designed hole depth, etc., the drill bit and the reamer should be lined up and used alternately. Use the larger one first, then the smaller one. At the same time, the smaller inner diameter should be used first, and then the larger inner diameter should be used. During the rotation process, it should be ensured that the queued drill bits and reamers can go down to the bottom of the hole normally, so as to avoid sweeping the hole and sweeping the residual core.

(2) After the drilling is confirmed, a vernier caliper must be used to precisely measure the outer and inner diameters of the drill bit and the reamer, as well as the height of the impregnated drill bit, and make a record as the basis for the next selection of the drill bit size.

1. The drill bit and the reamer must be reasonably matched

(1) The outer diameter of the reamer should be O.3mm--O.5mm larger than the outer diameter of the drill bit, and the hard rock layer should not be larger than O.3mm. If the outer diameter of the reamer is too large, the amount of reaming will increase, the wear will increase, and the drilling efficiency will be low. If the outer diameter of the reamer is too small, it will not play the role of reaming and maintaining the diameter.

(2) The inner diameter of the dth hammer button bits and the free inner diameter of the circlip must be reasonably matched. If the free inner diameter of the circlip is too large, the core cannot be taken or clamped firmly, resulting in falling off or too much residual core; if the free inner diameter of the circlip is too small, it is easy to cause core blockage. Therefore, before drilling down each time, pay attention to checking the size of the drill bit and the matching size of the circlip. The airport should prepare 2 to 3 kinds of circlips for selection.