Pore-Water Extraction from Unsaturated Tuffs Using One-Dimensional Compression

Mower, Timothy E.; Higgins, J. D.; Yang, In Che; ,

Pore-Water Extraction from Unsaturated Tuffs Using One-Dimensional Compression

by Timothy E. Mower, PRC Environmental Management Inc, Denver, United States,
J. D. Higgins, PRC Environmental Management Inc, Denver, United States,
In Che Yang, PRC Environmental Management Inc, Denver, United States,

Document Type: Proceeding Paper

Part of: High Level Radioactive Waste Management 1991

Abstract:

To support the study of the unsaturated-zone hydrochemistry at Yucca Mountain, Nevada, a one-dimensional compression system was developed and tested to extract unaltered and uncontaminated pore-water samples from unsaturated tuff. The major components of the compression system include a high strength steel-alloy corpus ring and nickel-alloy sample sleeve that confine a core sample, and a base platen and piston for application of the axial stress. The base platen and piston are fitted with drainage grooves to allow pore water to drain during compression. Results obtained using the compression system indicate that pore-water samples could be obtained from nonwelded-tuff cores that had initial moisture contents as small as 8 percent (by weight) and from welded tuff cores that had initial moisture contents as small as 6.5 percent (by weight). For the ambient moisture conditions of tuffs present at Yucca Mountain, the one-dimensional compression system is more effective for extracting pore water than a previously tested triaxial-compression device.

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