NON-DARCIAN FLOW IN CLAY SOILS

ALTHOUGH THE FLOW OF FLUIDS THROUGH POROUS MEDIA IS OFTEN DESCRIBED BY AN EMPIRICAL RELATIONSHIP WHICH WAS ESTABLISHED BY DARCY IN 1856, ITS APPLICABILITY TO THE FLOW OF WATER THROUGH CLAY SOILS IS SERIOUSLY QUESTIONED BY MANY INVESTIGATORS, AND A CONSIDERABLE NUMBER OF DEVIATIONS HAVE BEEN REPORTED.EVIDENCE FOR THESE DEVIATIONS IS REVIEWED AND DISCUSSED, AND THE POSSIBLE CAUSES FOR NON-DARCIAN FLOW THROUGH CLAYS ARE ATTRIBUTED IN LARGE MEASURE TO THE VARIATIONS IN THE PROPERTIES OF THE BOUND WATER, AS INFLUENCED BY THE PHYSICO-CHEMICAL PROPERTIES OF THE CLAY-WATER SYSTEM.FINALLY, A FAIRLY GENERAL FOUR-PARAMETER FLOW RELATION, WHICH DESCRIBES MOST OF THE AVAILABLE EXPERIMENTAL DATA, INCLUDING DARCIAN FLOW AS A SPECIAL CASE, IS POSTULATED.(A)