Flow around a vertical sheetpile embedded in an inclined stratified medium

Abstract

The steady‐state flow around a vertical sheetpile embedded in an inclined stratified porous medium underlain by an impervious boundary is studied experimentally. The porous medium is a synthetic ‘sandstone’ composed of alternating thin layers of two sand‐epoxy mixtures with coefficients of permeability differing by a factor of 18. The problem is subjected to a coordinate transformation based upon considering the layered system as homogeneous and anisotropic, and a graphical flow net solution is obtained for the streamlines, potential distribution, and flow quantity. By consideration of the porous medium as a semi‐infinite half‐space and use of the same coordinate transformation, complex variable theory and conformal mapping techniques are used to obtain an approximation for the flow quantity and exit gradient variation. Experimental results on streamlines, potential distribution, flow quantity, and exit gradient were obtained from a model study, and these results were found to exhibit some variations from the theoretically predicted results, especially with regard to the flow quantities. A systematic study of possible experimental errors suggests that these variations cannot be attributed wholly to experimental sources and leads to the implication that perhaps the effective permeability of a stratified porous medium cannot be determined by considering the system as homogeneous and anisotropic.