Reverse-circulation Hard Rock Drilling Technology with Pneumatic DTH Hammer for Rotary Drilling Rig

Abstract:

In order to solve the construction difficulties of the rotary drilling rig in the hard rock strata, by drawing on the mature process method in the field of geological drilling, the method and equipment for the reverse drilling process of the pneumatic DTH hammer for the rotary drilling rig are developed. Without changing the structure of the rotary drill rig, the reverse drilling tools of the pneumatic DTH hammer are applied to achieve fast hard rock drilling to solve the difficult cuttings expelling in large diameter drilling, and the environmental requirements are met. According to the construction requirement of large diameter pile foundation and the application characteristics of the DTH hammer, the reversed circulation pneumatic DTH hammer drilling tool is designed, the double channels for air and water with large center diameter can meet air inletting and cuttings expelling. Reversed circulation double drill pipes are concentric type with reliable sealing. The hexagon structure is used for the drilling tools connection. The feasibility of the technology and equipment are verified in the construction of Xiamen subway.