Laboratory Investigation of Stress-Dependency and Anisotropy of Hydraulic Conductivity
O. A. Owolabi, M. Rashvard, Y. Liu and J. Li
Morgan State University, Baltimore, Maryland, USA
In the past, the field data had indicated that stress-dependent and anisotropic hydraulic conductivity of aquitards in an aquifer system plays an important role in the vertical movement or subsidence. However, investigation of how the aquifer system is in response to the stress-dependent and anisotropic hydraulic conductivity is little. For simplicity of investigation, in groundwater models the hydraulic conductivity usually is assumed to be constant. In reality, however, aquitard’s hydraulic conductivity may be not only a function of spatial distributions, but also varies with time and in different directions. In this investigation, the hydraulic conductivity is found to be a function of changing effective stress or hydraulic head that are due to groundwater withdrawal from the aquifer and the changes in the aquitard storage. A conventional triaxial apparatus has been customized to run the permeability test in order to investigate the stress dependency and anisotropy of hydraulic conductivity of compressible soils in the laboratory. The lab investigations have been conducted for both the vertical and transverse hydraulic conductivity. A nonlinear model may be introduced to approximately describe the variation of hydraulic conductivity with effective stress, and/or volumetric strain. The effects of stress-dependent and anisotropic hydraulic conductivity in land subsidence has been analyzed and discussed thoroughly. The results can be applied to the numerical simulation of aquifer system movement due to groundwater extraction using the hydraulic conductivity that is stress-dependent and anisotropic.
Morgan State University
Wednesday, January 4
1:30 PM – 3:00 PM