Modeling Flow in Fractured Medium: Uncertainty Analysis with Stochastic ContinuumApproach

摘要

For modeling groundwater flow in formation-scale fractured media, no generalmethod exists for scaling the highly heterogeneous hydraulic conductivity data to model parameters. The deterministic approach is limited in representing the heterogeneity of a medium and the application of fracture network models has both conceptual and practical limitations as far as site-scale studies are concerned. This study investigates the applicability of stochastic continuum modeling at the scale of data support. No scaling of the field data is involved, and the original variability is preserved throughout the modeling. Contributions of various aspects to the total uncertainty in the modeling prediction can also be determined with this approach. Data from five crystalline rock sites in Finland are analyzed. The issues considered include stochastic versus deterministic nature of the data, statistical similarities and differences between various data sets, types of theoretical distributions, distribution parameters and their confidence limits, spatial trends and autocorrelation structures, role of measuring equipment detection limit in these analyses, and needs for erogodicity assumptions. A stochastic treatment is applied for data from which significant fracture zones are excluded. (Copyright (c) Valtion teknillinen tutkimuskeskus (VTT) 1994.)