Taking the foundation pit supporting engineering of Shekou cruise center as an example,we study the selection of foundation pit supporting structure in the foundation of riprap backfill.Through obtaining the construction parameters and calculating the permeability coefficient through field test,we select the structural scheme of plastic concrete occluding pile.In this paper,we introduce the mechanical characteristics and calculation method of the plastic concrete bitten pile,and find out the practical design method with the measured data.The plastic concrete piles are proved safe and feasible in the riprap coastal foundation pit.