Slope instability caused by small variations in hydraulic conductivity

Journal of Geotechnical and Geoenvironmental Engineering
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Abstract

Variations in hydraulic conductivity can greatly modify hillslope ground-water flow fields, effective-stress fields, and slope stability. In materials with uniform texture, hydraulic conductivities can vary over one to two orders of magnitude, yet small variations can be difficult to determine. The destabilizing effects caused by small (one order of magnitude or less) hydraulic conductivity variations using ground-water flow modeling, finite-element deformation analysis, and limit-equilibrium analysis are examined here. Low hydraulic conductivity materials that impede downslope ground-water flow can create unstable areas with locally elevated pore-water pressures. The destabilizing effects of small hydraulic heterogeneities can be as great as those induced by typical variations in the frictional strength (approximately 4°–8°) of texturally similar materials. Common “worst-case” assumptions about ground-water flow, such as a completely saturated “hydrostatic” pore-pressure distribution, do not account for locally elevated pore-water pressures and may not provide a conservative slope stability analysis. In site characterization, special attention should be paid to any materials that might impede downslope ground-water flow and create unstable regions.

Publication type Article
Publication Subtype Journal Article
Title Slope instability caused by small variations in hydraulic conductivity
Series title Journal of Geotechnical and Geoenvironmental Engineering
DOI 10.1061/(ASCE)1090-0241(1997)123:8(717)
Volume 123
Issue 8
Year Published 1997
Language English
Publisher ASCE
Description 9 p.
First page 717
Last page 725
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