Diskrete Simulation des Schadstofftransports in klueftigem Fels unter Beruecksichtigung des Mischungsverhaltens im Verschneidungsbereich von Trennflaechen

A large number of disposal sites is built on subsoil consisting of jointed rock. In order to assess the potential danger of contamination for the environment, it is necessary to employ an appropriate numerical model for the simulation of contaminant transport in fractured rock. Contaminant transport in fractured rock can only be described realistically under consideration of different transport mechanisms and transport processes. One of the most important processes in the process of mass mixing at fracture entersections. In this paper a discrete model for the simulation of contaminant transport in fractured rock with consideration of the mass mixing process at fracture intersections is developed. The new mass mixing model for fracture intersections is based on the finite element method and allows the description of contaminant transport by streamtube routing under consideration of dispersion and diffusion. Back-analyses based on this mixing model are in very good agreement with the results of laboratory tests which were carried out at the Institute for Foundation Engineering, Soil Mechanics, Rock Mechanics and Waterways Construction of Aachen Technical University. On the basis of this proposed mass mixing model, a two-dimensional discrete finite element program system FESSTFR was developed for the simulation of contaminant transport in fractured rock. Apart form the newly developed mass mixing model also the limiting theoretical cases of streamtube routing and complete mixing are implemented in the program system. (orig.)SIGLEAvailable from TIB Hannover: RN 4771(35) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman