Analysis and Settlement of Partially Stiffened Single and Group of Two Floating Granular Piles

Ground improvement is a technique which a geotechnical engineer normally faces whenever soft soil is encountered. There is a need to look for some economic and feasible option for the provision of foundation in such cases, and one of the option available, is to use the granular pile (GP). The present paper analyzes a single partially stiffened floating and group of two partially stiffened floating GPs. Partial stiffening simply means that the material of the GP is replaced partially in the top region of granular pile by some material, having good mechanical properties i.e. higher deformation modulus e.g. geo-grids, stiffened deep cement mixing, etc. Mathematical formulation and its numerical solution is developed to incorporate the stiffening of granular pile at top portion in the analysis to study its behavior. The effect of stiffening factor i.e. ratio of modulus of deformation of stiffened to un-stiffened portion of GP and percentage length of stiffening i.e. ratio of length of stiffened portion to the total length of the pile are studied on various parameters such as settlement influence factor at top, settlement interaction factor, settlement reduction factor, normalized shear stress distribution along the length of the pile and percentage load transferred to base. As obvious, the settlement influence factor at top decreases with the increase in the stiffening parameters viz. stiffening factor and percentage length of stiffening.