Coupled consolidation theory with non-Darcian flow

Abstract

Abstract Some evidence shows that the flow of pore water in the soil may not obey Darcy's law that is a basic assumption in most of the existing consolidation theories. One of the nonlinear flow relationships, non-Darcian flow (described by the threshold gradient i l and exponent m ), was incorporated in the coupled consolidation theory in this paper. The corresponding highly nonlinear continuity equations were solved numerically with the aid of an approximate procedure. A program was developed based on these equations and the finite element formulations are presented here. The program was verified against established theoretical solutions and the results were found to be satisfactory. Finally, the influence of non-Darcian flow on consolidation was investigated. It was found that (1) the consolidation rate would slow down when non-Darcian flow is considered. However, the effect of non-Darcian flow on consolidation is significant only when i l ⩾40 and m ⩾1.5; (2) non-Darcian flow does not significantly change the patterns of deformation and excess pore pressure distribution; (3) stress history has significant effect on the consolidation rate, especially on the dissipation of excess pore pressures.