ABSTRACT
Two criteria are currently used for verifying integrity of geological barriers. We shall describe them as mechanical criterion and hydraulic criterion. The mechanical criterion states that the integrity of the geological barrier is deemed to be proven if the state of stress which is computed in a model calculation is unsuitable for creating dilatancy deformations in the surrounding rock. The hydraulic criterion is fulfilled if the minimal principal stress in a model calculation is higher than the respective, depth-dependent hydraulic pressure of brine. There is currently no scientific consensus whether the proof of barrier integrity must only fulfil one of the two criteria or whether the criteria are mutually independent and must be seen as complementing each other. New tests on large rock salt cores on which a hydraulic fluid pressure is imposed in addition to the triaxial mechanical stress will be presented. As a result of the tests, it can be demonstrated that the aforesaid criteria must be considered as mutually independent.
