Analytical solution for consolidation of composite ground with granular columns accounting for consolidation deformation of pile

The whole cross section of a granular columns and soil around pile were regarded as an element to analyze. According to the equivalent relationship of the seepage discharge to the volumetric change, the equations for the consolidation of composite ground with granular columns were derived using the concept of average excess pore water pressure; and the consolidation deformation of pile was considered. Through the initial and boundary conditions of the composite foundation and the assumption of the equal strain, the equations were solved by separation of variables. The average excess pore water pressure and average percent consolidation of granular pile and its surrounding soil were obtained; and the degree of consolidation of the composite foundation was acquired. Finally, an example was given for calculation and analysis. Results drawn from this paper have been compared with the existing references’ results; when the diameter ratio of composite ground with granular columns was large, the results are in good agreement; and the diameter ratio was small, the differences come to obvious.