Blowout prevention hole apparatus for hole drilling construction

The utility model relates to a jet orifice preventing device for boring construction, which is characterized in that a draught tube which is freely sleeved outside a drill pipe in a close way is arranged, and a draught cavity is left between the draught tube and the drill pipe; a draught separating box with a negative-pressure separating cavity is arranged; an airflow channel and a deslagging channel are respectively arranged between the draught tube and the draught separating cavity; and the draught separating box is communicated with a negative-pressure pumping pipeline to form negative pressure inside the box. The utility model can avoid the accidents caused by jet orifices, ensure the safety of the boring constructing personnel and put an end to gas ultralimit. During the process of boring construction, the utility model pumps while boring without influencing the normal construction of boring, and can facilitate the boring deslagging and ensure the continuous construction of jet orifice boring.