Abstract: Methods and devices for the execution of core drillings in a material by a drilling unit, which makes use of a drill bit, and such drill bits that are made up of a hollow cylindrical core barrel, which has an end plate at its rear end and abrasion elements, which serve the abrasion of material, at the front end as well as at least two high-pressure jet nozzles, which can be connected with a high-pressure source of a blasting medium. The high-pressure jet nozzles are arranged on the inner surface of the core barrel and/or its end plate and are oriented into the inside of the core barrel. As a result of a combined forward motion and rotation of the drill bit, a drilling core is formed from which an abrasion takes place by means of the blasting medium, whereby overburden is removed from the drill bit.