Description: Das Projekt "Inverse zweidimensionale Modellierung des Transports in Kluftnetzwerken" wird vom Umweltbundesamt gefördert und von Universität Heidelberg, Institut für Umweltphysik durchgeführt. Two dipole tracer experiments were performed in a fractured rock at the Grimsel Test Site in February/March 1993. In both experiments NaCl was used as a tracer. The extraction rate was twice the injection rate. In the second experiment injection and extraction were interchanged (Reverse-Experiment). Long tailing was characteristic of the breakthrough curves in both experiments. The tests were interpreted using a single facture allowing for diffusion into an immobile matrix. We were able to interpet the breakthrough curves for both experiments by one unique set of parameters, describing transport and baseflow. Uniqueness could only be achieved when using the information of both experiments. We conclude that performing a Reverse-Experiment is an indispensable tool for parameter identification in dipole tracer tests. A sensitivity analysis proved that not only matrix diffusion is responsible for the tailing in the breakthrough curves but also transversal dispersivity. Further, the typical exchange time between mobile and immobile media was too small to be attributed to matrix diffusion in the strict sense which will causetailing even at large spatial and temporal scales. Analysis of the covariance matrices showed that the parameters have small errors but high correlation. Methods and techniques used: Glaerkin-Finite-Elemente Method, Newton-Raphson, Levenberg-Marquardt, Preconditioned Conjugate Gradient Method, Maximum-Likelihood-Theorie, Confidence Ellipses.
Types:
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Heidelberg ? Tracer ? Korrelationsanalyse ? Dispersion ? Schadstoffausbreitung ? Sensitivitätsanalyse ? Modellierung ? Diffusion ? Kenngröße ? Gestein ? Dipol ? Finite Elemente ?
Region: Baden-Württemberg
Bounding box: 9° .. 9° x 48.5° .. 48.5°
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 1993-01-01 - 2024-11-29
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