The large diameter Dth hammer has achieved good results in the drilling of block stone, boulder, moderately weathered and slightly weathered hard rock strata,rock drilling tools, which meets the smooth pile formation of prestressed pipe piles. Through the actual construction, it was found that the rock debris string hole phenomenon did not have a greater impact on the pile-hole guide pile sinking. (III) How to control the verticality of guide hole Countermeasures: Start the air compressor to drive the Dth hammer to start drilling. During the initial drilling, the drilling speed shall be low, the verticality of the drill pipe shall be rechecked frequently, and it shall be adjusted in time. The down-hole hammer and casing drilling technology is used to guide the hole, which not only solves the problem of insufficient outlet air volume, but also controls the verticality of the guide hole. III. Guarantee of construction period of down-the-hole hammer There are about 200 prestressed pipe piles to be drilled in the concentrated area of weathered and slightly weathered spheres or interlayers in this project. Two down-the-hole hammer drills are arranged to enter the site for construction. Each down-the-hole hammer drill can drill about 5 piles every day. The drilling operation of about 10 piles is completed every day. The drilling work in this area is completed within 20 days. After this part of hole guiding operation is completed, a down-the-hole hammer drill is left as a standby, and hole guiding operation is carried out when the remaining pipe pile construction area needs hole guiding. After receiving the Letter of Acceptance from Party A, immediately organize the mobilization of mechanical equipment and pipe pile materials. This project plans to arrange 2 down-the-hole drills for pipe pile hole guiding operation. During the construction process, the number of hole guiding equipment can be adjusted and increased according to the actual situation, so as to ensure the realization of the total construction period target. END Source: Baidu Library We are committed to protecting the copyright of the author, the source of the content has been marked,Tapered Rock Bit, only for the dissemination and sharing of knowledge. No other commercial profit, if there is infringement, please contact us to delete. Push Return to Sohu to see more Responsible Editor:. wt-dthtools.com