Analytical solution for consolidation of composite foundation accounting for variation of soil horizontal permeability coefficient

To incorporate the detrimental influence on the surrounding soil due to column installation, three types of variation patterns of the horizontal permeability of soil in the disturbed soil zone were considered, including a constant and a linearly changed permeability coefficient within the disturbed soil zone and a linearly changed permeability coefficient within the whole influence zone. By using a new initial condition derived from the equilibrium condition and the equal strain assumption, the solutions for excess pore water pressure within the surrounding soil and the column were obtained, respectively. The column consolidation was incorporated into the definition of average consolidation degree of a composite foundation. Then the solutions for the total average consolidation degree defined by stress and deformation respectively were put forward. The results indicate that the solution of total average consolidation degree in terms of stress is equal to that in terms of deformation. Finally, the influences of four parameters on the consolidation behavior of composite foundation were analyzed, and several available solutions were compared with the present solution. The results show that the greater the ratio of the maximum to the minimum coefficient of horizontal permeability coefficient of soil is, the slower the consolidation is; the less the size of disturbed soil zone is, the faster the consolidation is; the stiffer the column is, the faster the consolidation is.