On the usability of different optical measuring techniques for joint roughness evaluation

Bulletin of Engineering Geology and the Environment - The roughness of rock discontinuities is an important input parameter for mechanical models of rock masses. To reliably calculate roughness...     

Einfluss der Korngrößenverteilungen nichtbindiger homogener Böden auf hydraulischen Grundbruch

Grundwasser - Die vorliegende Arbeit beschäftigt sich mit dem Einfluss der Korngrößenverteilungen von nichtbindigen homogenen Böden auf den Mechanismus des hydraulischen...     

Untersuchungen zum hydraulischen Grundbruch in Baugruben in homogenen Böden

In this study, two problems are discussed with respect to hydraulic heave. Firstly, the verification of safety against hydraulic heave according to DIN EN 1997-1 (2014-03) yields different results depending on the considered limit state conditions. It is demonstrated that this problem can be solved by using hydraulic gradients as a parameter for the limit state condition. Secondly, the form of a potential failure body appearing in three-dimensional groundwater models is unknown. Based on numerical analyses, it has been shown that an average hydraulic gradient that is determined by using an assumed three-dimensional failure body with the width suggested by Terzaghi for two-dimensional cases leads to a quicksand condition in an infinitesimal soil column directly adjacent to the wall, when its value is equal to the critical hydraulic gradient of the soil. The model tests show that Terzaghi’s method or quicksand condition refers to certain deformations in an excavation base. The hydraulic gradient required for the first sign of a quicksand condition in loose sands may be lower than the theoretically required hydraulic gradient, whereas it is higher in dense sands.     

Pumpspeicherbecken im Karstgrundwasserleiter des Weißen Jura der Schwäbischen Alb

Extensive geological and hydrogeological investigations have been undertaken for the planned pumped-storage hydroelectric power plant in “Blautal” (Swabian Alb, Germany) in order to characterise the Jurassic karst aquifer in which the lower reservoir will be constructed. The preferred option for the plant setup is to integrate the lower reservoir into the groundwater without sealing. Therefore, in order to reliably predict the impact of the pumped storage plant operations on the surrounding drinking water wells and groundwater dependent ecosystems, a comprehensive database has been developed to assess the hydraulic conditions of the karst aquifer. A large scale geological site investigation was carried out to characterise the rock mass and extensive hydraulic tests were performed in many boreholes. The results of the hydraulic characterisation were then implemented in a three dimensional flow model. In this paper, the first results of the geological and hydrogeological investigations are presented and discussed.     

Large-scale lateral spreading and related mass movements in the Northern Calcareous Alps

Lateral spreading is an important geotechnical phenomenon in the Hallstatt zones of the Northern Calcareous Alps where rigid limestones overlie marls and salt clays. Following the last glaciation, mass movements have developed with a general spreading of limestone blocks resulting in a complicated jigsaw puzzle of rock. Two typical examples from Mt. Sandling and Mt. Raschberg in the Northern Calcareous Alps of Austria are discussed.