Abstract: The disclosure describes an expanding drill device for expanding a pilot bore by moving the expanding drill device along a specified drilling line comprising: a housing; a drill head that has a cutting wheel which is arranged on the drill side of the expanding drill device so as to be rotatably mounted and driven about a rotational axis and relative to the housing and on which at least one drill tool for loosening the ground or the rock is arranged; and a drill-side connection for producing a connection to a pipe section located in the pilot bore on the drill side, wherein the drill side centrally has at least one receiving chamber for the loosened ground or the loosened rock, said receiving chamber being connected to a material conveyor device of the expanding drill device.

Abstract: A drill head for creating a substantially vertical borehole in the ground, includes a body connected to a rotational drive of a drilling device; drilling tools on the body, for loosening the ground at a working face of the borehole; suctioning elements for leading away the loosened ground, which can be connected to a pump, and the suctioning elements include an opening region on the body and with at least one opening in the region of the drilling tools. The opening region has may have an elongate extent, and is connected to a suction box with an opening for connecting to the pump. The loosened ground can be sucked through the opening into the suction box with the pump. The suction box is tapered in width from the opening toward the connection opening, and that the height of the suction box increases from the opening toward the connection opening.

Abstract: A method for monitoring overburden during excavation in soil, in which the soil pressure exerted by the soil (10) on an excavation device driven through the soil (10) is monitored by means of a pressure control element (5) extended from the circumference (3) of the driving device. An excavation device for carrying out the method has a pressure control element (5) which is arranged on the circumference (3) of the excavation device and can be extended beyond the circumference (3) of the excavation device.

Abstract: A drill head for expanding a pilot bore in order to create a borehole having a borehole wall as a result of loosening rock surrounding the pilot bore in the region of a working face, which extends in a substantially right-angled manner to the pilot bore, including a basic body including a connection element for a pilot bore string including at least two tool holders, in that at least one tool holder is at a greater spacing radially from the basic body than the at least one other tool holder such that there is at least one outer and one inner drilling tool which are movable into engagement with the working face, and the at least one inner drilling tool and the at least one outer drilling tool are each arranged offset at an angle in relation to the working face.