Calculation and analysis on load transfer behaviors of reamed precast concrete pile under core pile bearing

Reamed precast concrete (RPC) pile is composed of core precast concrete pile and peripheral reamed material condensate. Compared with conventional single material pile, the load transfer behaviors of RPC pile is more complex due to the cooperative bearing mechanism of the core precast concrete pile, reamed material, and surrounding soil. To investigate the load transfer characteristics of the core pile, reamed body, and surrounding soil in the RPC pile under core pile bearing, based on some experimental results, an elastic-failure model and an ideal elastic-plastic model are adopted to characterize the interaction performance of the core pile – reamed body interface and the reamed body – soil interface, respectively. Taking into account the coupling effect of the two interfaces, a load transfer analysis model is established for the RPC pile under core pile bearing. And the calculation method for the internal forces and deformation of the RPC pile is further provided. The applicability of the proposed theoretical method is examined by comparing the calculations with the results of the field test and engineering case, and the load transfer characteristics of the RPC pile under core pile bearing is further discussed. The analysis results indicate that the peripheral reamed body can effectively transfer the core pile load to surrounding soil, and has a “diameter expansion” effect on the core pile. Increasing the diameter of the reamed body can improve the bearing performance of the composite pile, however, thicker reamed body may also restrict the play of the bearing capacity of the core pile. Increasing the reamed body stiffness can improve the core pile load transfer efficiency, which is conducive to the joint action of the core pile and peripheral reamed body. In engineering design and practice, the interaction between core pile, reamed body and surrounding soil can be coordinated by adjusting the thickness and performance of the peripheral reamed body.