Mounted with carbide bullet teeth at the bottom of the barrel,drilling in to the pile around by Circumcision.The core breaks along joints or bedding planes fractures.The core is taken out with the combined working of carbide teeth and the drill bottom.

Suitable for heavily 600–1000 kPa weathered rock fragment strata, and   15-60 Mpa moderately to slightly weathered rock strata.The core diameter increases accord to the increasing of pile diameter,so the larger the pile diameter is, the lower the core taking successful rate and vice versa.