Modeling a ponded infiltration experiment at Yucca Mountain, NV

Conference · Fri Dec 30 23:00:00 EST 1994

OSTI ID:60951

Hudson, D B; Guertal, W R ^[1]; Flint, A L ^[2]

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1. Foothill Engineering, Inc., Mercury, NV (United States)
2. Geological Survey, Mercury, NV (United States)

One-dimensional and two-dimensional radial flow numerical models were used to evaluate the results for a 60.5 h ponded infiltration experiment done around a 24 m deep, 0.15 m diameter, cased borehole at Yucca Mountain, NV. Nine distinct morphological horizons in the soil profile has been identified; physical and hydraulic properties had been measured for each horizon; and a porosity profile at the borehole had been measured. During the infiltration experiment, 10 cm of water was ponded in a 3.5 m diameter infiltrometer around the borehole, the volume of water applied was measured, and water content profiles were measured with a neutron moisture meter. The infiltrometer applied 86.9 cm of water during the first 60.5 h of infiltration, but only 52.8 cm of additional water was measured in the borehole profiles. Assuming a linear relationship between cumulative infiltration (I) and the square root of time (t{sup 0.5}), an experimental sorptivity of 11.5 cm h{sup {minus}1} was estimated for the first 4.5 h of infiltration. An assumed washout zone around the borehole casing accounted for the discrepancy between the measured water content profiles and the applied water. A uniform property, 1-D model with an applied flux upper boundary described by the sorptivity confirmed the probable washout zone, and indicated that significant lateral flow into the dry soil around the infiltrometer could occur. A 2-D radial flow model with the same properties and upper boundary demonstrated that significant lateral flow occurred. The upper boundary in this model caused the upper portion of the profile to drain. This suggested using a saturated upper boundary to keep the upper portion of the profile saturated. When the saturated upper boundary was used, the permeability of the soil was decreased from the measured value of 3.28 E-11 m{sup 2} to 1.5E-12 m{sup 2} so that the simulated wetting front at a similar depth as the observed wetting front after 60.5 h.

• Research Organization: American Society of Civil Engineers, New York, NY (United States); American Nuclear Society, La Grange Park, IL (United States)
• OSTI ID: 60951
• Report Number(s): CONF-940553--Vol.4
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
54 ENVIRONMENTAL SCIENCES
99 GENERAL AND MISCELLANEOUS
ANISOTROPY
FLOW MODELS
GEOLOGIC FORMATIONS
HIGH-LEVEL RADIOACTIVE WASTES
HYDRODYNAMICS
MATHEMATICAL MODELS
PERMEABILITY
RADIOACTIVE WASTE DISPOSAL
SITE CHARACTERIZATION
TWO-DIMENSIONAL CALCULATIONS
WATER SATURATION
YUCCA MOUNTAIN
Yucca Mountain Project