Abstract: Process and device for sealing barrier constructions in subterranean galleries, especially in salt mines. In the process, a fluid sealing medium is filled into a hollow space and is maintained at overpressure relative to the pressure of a stressing medium. With the device, a hollow space is filled with a sealing medium, maintained below overpressure, and positioned between the part of the gallery to be protected and the part of the galley in which a stressing medium is present. The sealing medium is stressed with a preset pressure and at the pressure of the stressing medium. The hollow space has a pressure shaft, in which the sealing medium stands at a predetermined level. The part of which is located above the level of the sealing medium is connected with the gallery in which the stressing medium stands. Through this, it is ensured that a specific overpressure is always present in the hollow space.