Study of trench covers to minimize infiltration at waste disposal sites. Task II report. Laboratory evaluation and computer modeling of trench cover design. Vol. 2
Laboratory tests were conducted on geologic mateials selected for use in covers for waste disposal sites: the materials included fine-grained loess and glacial till, used in covers and liners for waste disposal sites, and various coarse-grained materials used in drainage systems associated with covers. The physical, engineering, and hydrologic properties of these materials were determined in respect to their performance in trench covers. A dual-energy, gamma-ray attenuation apparatus was constructed to measure simultaneously the moisture content and density of a laboratory soil column. Measurement of moisture content during initial experiments indicated that moisture movement in unsaturated materials is inhibited by the presence of an interface between materials of highly contrasting texture as predicted by mathematical modeling. One-dimensional and two-dimensional models were used for computer simulations of moisture movement through several cover designs. The modeling indicated that a layer of coarse-textured, unsaturated material overlain by a layer of fine-grained material, could serve as a barrier to moisture movement. The effectiveness of the barrier is related to the contrast in texture and saturated hydraulic conductivity between the two layers. Where moisture breakthrough does occur, the moisture content of the overlying layer is less than saturation and the pressure head at the interface is less than zero. The simulation also suggested that moisture buildup in the fine-grained layer overlying the coarse-textured layer will flow laterally down-slope above the interface, prior to breakthrough. (38 refs.)
- Research Organization:
- Illinois State Geological Survey, Champaign (USA)
- OSTI ID:
- 5879859
- Report Number(s):
- NUREG/CR-2478-Vol.2; ON: DE83903082
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COVERINGS
MATERIALS TESTING
RADIOACTIVE WASTE DISPOSAL
LOW-LEVEL RADIOACTIVE WASTES
BENCH-SCALE EXPERIMENTS
COMPUTERIZED SIMULATION
DESIGN
MOISTURE
PHYSICAL PROPERTIES
SOILS
UNDERGROUND DISPOSAL
MANAGEMENT
MATERIALS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
SIMULATION
TESTING
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
052002* - Nuclear Fuels- Waste Disposal & Storage