Abstract: The invention relates to a ground-working machine and a method for producing wall panels, with the ground-working machine having at least two elongate drilling and mixing tools arranged parallel to each other, which comprise a rod-form base body, on which a first screw conveyor and at least one second screw conveyor are arranged, the second screw conveyor being axially spaced apart from the first screw conveyor. According to the invention it is provided that at least on one drilling and mixing tool at a lower end the first screw conveyor is formed with an outer diameter that is greater than an outer diameter of the second screw conveyor which is arranged above the first screw conveyor.