Abstract: Process and apparatus for consolidating, sealing and stabilizing a predeterminable area in the ground, particularly for making foundations, underpinnings or seals in a building site, by injecting at least one hardening liquid material in a high energy liquid jet into the ground, accompanied by the simultaneous injection of a gaseous material, characterized in that for the injection of the gaseous material, at least one discrete gas jet is formed and injected separately from the liquid jet and is located in the vicinity of the exit port of the liquid jet and guided at a distance from the liquid jet.

Abstract: In a slotted wall milling cutter for excavation work, the milling wheel arranged laterally of a bearing bracket, mounted in rotary manner in the latter and equipped over its circumferential surface with radially projecting milling teeth has at least one milling tooth pivotable at right angles to the circumferential direction. This fixture permits a complete working of the entire milling cross-section.

Abstract: In the case of a plug connection for drilling or boring tubes, rods and worms for earth boring equipment with a male part and a female part, with a radial coupling for torque transfer and with an axial coupling having in the overlap zone of the male and female parts a locking device which can be introduced into an annulus for transferring axial forces, it is provided that the locking device is constructed as a multilink chain, which essentially extends around the entire annulus and which is introduced through the female part into the annulus via a single opening. This device provides a plug connection, which has a very simple construction and after extremely rapid installation is suitable for transferring very high forces.

Abstract: A slotted wall milling cutter for producing a slotted wall in the ground has a drive motor fixed to the cutter frame and a gear means positioned between the drive motor and two cutting wheel gears and which is partly arranged in recesses of a bearing bracket. The cutting wheel gear is constructed as a multistage planetary gear. A particularly high torque is made available on the cutting wheels with this arrangement. In addition, the cutting wheels can be constructed with a very high effective cutting width compared with the total slot width.