Abstract: In a method for producing a cased horizontal string bore extending from a well shaft, a starter drill pipe is driven into the rock mass surrounding the well shaft. A hydraulically driven drill motor is arranged in the starter drill pipe and rotates a drilling tool protruding from the leading end of the starter drill pipe. The drill motor is fixed against rotation and axial displacement by a clamping device. When the final depth of the string bore is reached, the drilling tool is retracted into the starter drill pipe by axial movement of the clamping device and a free space is formed at the drift face of the string bore. The free space is filled and sealed by injection of a quick-setting, expanding filling compound. Afterwards, the clamping device, the drill motor and the drilling tool are removed from the drill pipes.

Abstract: In a method for producing a cased string bore (5) extending from a well shaft (1) in the horizontal direction for the installation of a filter string, a starter drill pipe (13) and subsequently further drill pipes are driven into the rock mass (6) surrounding the well shaft through an opening (4) in the wall (2) of the well shaft (1) using a drive means (11) arranged in the well shaft. Arranged in the starter drill pipe (13) is a hydraulically driven drill motor (18) which drives in rotation a drilling tool (19) protruding from the leading end of the starter drill pipe (13) and is supported in the starter drill pipe (13) by means of a clamping device (21, 22) so as to be fixed against rotation and axial displacement, a partition sealing the starter drill pipe (13) being formed by means of the clamping device (21, 22).

Abstract: A go-devil (1) is inserted into a pipe end of a pipe (5) laid in place in trenchless manner by ramming or pressing and of which the earth core (7) shall be removed by a method of the invention, said go-devil being displaced longitudinally through said pipe and forcing the said earth core out at the other pipe end. The advance of the go-devil (1) takes place step by step by means of a length-variable actuator (10) bracing itself against the inside wall (4) of the pipe (5), said actuator after each forward stroke being returned into its initial position and its bracing being made to follow in the direction of advance by the amount of the step taken.