An Analytical Solution to Composite Modulus of Foundations Improved by Geosynthetic-encased Granular Columns

As a new technique in ground improvement, geosynthetic-encased granular columns (GEGCs) have a promising application in soft foundation. Based on the generalized plane strain assumption and the elasticity theory, an elastic analytical solution to composite modulus for foundations improved by GEGCs is proposed. The composite modulus of the foundation resting on a rigid base is derived in detail. To validate the current analysis, a comparison with the solutions proposed by Zhang Y.P. et al. is carried out. It is showed that the solutions developed by Zhang Y.P. et al. confirm the presented solution for the cases of an unreinforced column or a reinforced column, respectively. The interaction of the granular column, the surrounding soil and the geosynthetic encasement is taken into account in the composite modulus of the foundation in this paper. Moreover, the settlement of the foundation is also obtained. The proposed solution may be a simple and useful tool for design without laborious analytical efforts.