Grouted gravel pile is a new technique of piles for reinforcing soft soils. It has been successfully used in construction of projects of expressway and high-speed railway. In order to study the load transfer mechanism of the pile

under the assumption that the compression modulus is obeyed the exponential distribution in reinforced zone

and based on the solution of settlement in half-space under circular bearing plate

the settlements of different parts of grouted gravel pile composite foundation under loads are analyzed; and the formulas of axial force

lateral friction resistance along the grouted gravel pile

and settlement on the top of pile are derived. The practicability of this method is illustrated by a case study. It is shown that the theoretical calculation results are close to the actual measurement results. Therefore the deduced equations are reasonable.