Hydraulic importance of defects in vertical groundwater cut-off walls
- Univ. of Wisconsin, Madison, WI (United States)
The hydraulic importance of defects in vertical cut-off walls was assessed using a three-dimensional numerical model of groundwater flow. Soil-bentonite (SB), geomembrane (GM), and composite geomembrane-soil (CGS) walls were modeled. Defects that were simulated included inadequate keys, windows in SB walls, defective joints in GM walls, and windows (in the shell) and defective joints (in the GM) in CGS walls. Fully and partially penetrating defects were evaluated. Results of the simulations show that flow rates are significantly affected by how far a defect penetrates through the wall, i.e., whether defects are fully or partially penetrating. Partially-penetrating defects are hydraulically insignificant, whereas fully penetrating defects can govern flow rate if sufficiently permeable. Hydraulic conductivity of a defect is far more important than size or location of the defect. Fully-penetrating defects having moderate or low hydraulic conductivity (<10{sup -5} cm/s) are often unimportant. However, flow rates can be three orders of magnitude higher than expected when a very small (< 2% of wall), but permeable (>10{sup -3} cm/s) fully-penetrating defect exists. Location of the defect (i.e., horizontal and vertical position) has practically no effect on flow rate.
- OSTI ID:
- 567794
- Report Number(s):
- CONF-971032-; CNN: Grant CMS-9157116; TRN: 98:000358-0013
- Resource Relation:
- Conference: In situ remediation of the geoenvironment conference, Minneapolis, MN (United States), 5-7 Oct 1997; Other Information: PBD: 1997; Related Information: Is Part Of In situ remediation of the geoenvironment; Evans, J.C. [ed.]; PB: 622 p.
- Country of Publication:
- United States
- Language:
- English
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