Bearing Characteristics of Screw-Groove Piles: Model Test and Numerical Analysis.

Screw-groove piles, a new type of precast pile, are economically and environmentally friendly and improve the load-bearing performance of piles through a unique screw-groove structure. To reveal the load-transfer characteristics and bearing mechanism of the screw-groove pile, the axial force, load-settlement curve, skin friction, bearing capacity, and response characteristics of the foundation for piles under vertical loading were analyzed. Furthermore, a parameter analysis of the ultimate bearing capacity and material utilization of screw-groove piles was performed using the finite element method. The results demonstrate that the screw-groove pile had an ultimate bearing capacity 1.85 times higher than that of the circular pile, and its material utilization rate was 2.85 times higher. The screw-groove surface end resistance and pile-tip resistance formed a multipoint vertical bearing mode. It efficiently utilized the soil's shear strength and mobilized a larger volume of surrounding soil to share the load. The screw-groove structure increased the pile-soil interaction surface, thereby increasing the skin friction resistance of the pile. Additionally, increasing the inner radius of the screw groove boosts the pile's bearing capacity but may reduce material utilization. An optimal screw-groove spacing balances both factors, while excessive groove thickness lowers material use. The pile shows high sensitivity to soil parameters.