Sensitivity of calculated hydrological flows through multilayered hard rock to computational solution procedures

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Authors:Bixler, N. E.; Eaton, R. R.
Author Affiliations:Primary:
Sandia Natl. Lab., Fluid and Thermal Sci. Dep., Albuquerque, NM, United States
Other:
Pac. Northwest Lab., United States
Volume Title:Proceedings of the Symposium on groundwater flow and transport modeling for performance assessment of deep geologic disposal of radioactive waste; a critical evaluation of the state of the art
Volume Authors:Nicholson, Tom, chairperson; Cole, Charles
Source:No.NUREG/CP-0079, p.283-297; Symposium on Groundwater flow and transport modeling for performance assessment of deep geologic disposal of radioactive waste; a critical evaluation of the state of the art, Albuquerque, NM, May 20-21, 1985, chaired by Tom Nicholson and Charles Cole. Availability: NTIS, Springfield, VA, United States
Publication Date:1986
Note:In English. 6 refs.; illus.
Summary:Permeability and moisture content curves for partially saturated, fractured, welded tuffs, such as those found near the site of a prospective nuclear waste repository at Yucca Mountain, Nevada, are highly nonlinear. We illustrate, by means of a one-dimensional problem of infiltration into multilayered fractured tuff, the numerical instabilities that can arise when analyzing the flow in such porous materials. We compare the results obtained using two numerical schemes for treating the nonlinearities; the first uses a first-order Piccard iteration scheme to attain convergence at each time step; the second uses a second-order Newton-Raphson iteration procedure to attain convergence. The Piccard scheme converges when flow through the rock matrix dominates but does not converge when flow through fractures dominates. The Newton-Raphson scheme converges in both situations.—Modified report abstract.
Subjects:Engineering geology; Errors; Finite element analysis; Ground water; Igneous rocks; Infiltration; Mathematical models; Movement; Permeability; Porosity; Pyroclastics; Radioactive waste; Saturated zone; Statistical analysis; Surveys; Tuff; Volcanic rocks; Waste disposal; Nevada; Nye County Nevada; United States; Yucca Mountain
Record ID:1987079966
Copyright Information:GeoRef, Copyright 2018 American Geosciences Institute.
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