Vertical-inclined alternating composite steel pipe pile(VIACP) is a new green foundation pit support technology. A numerical experimental study on the mechanical properties of vertical-inclined combination piles with different pile inclination angles and lengths was carried out with a foundation pit in Longli County, Guizhou Province, as the research object. Results demonstrate that the VIACP reduces maximum deformation by 57.8% (20.07 mm) compared to traditional cantilever piles (47.57 mm), aligning closely with field monitoring data (16.94 mm). The parametric study shows that the maximum horizontal displacement of the pile decreases and then increases as the inclination angle (5 degrees-30 degrees) increases, with the minimum displacement (20.07 mm) at 20 degrees, which is the optimum angle. Increasing pile lengths lead to progressively reduced displacements followed by stabilization while alternating long-short pile configurations exhibit synergistic effects. Mechanically, axial forces and lateral friction resistance show negative correlations with inclination angles, while bending moments adopt an S-shaped distribution along pile depth with minimal sensitivity to angle variations. Mechanism analysis highlights that the inclined piles in the structure have a pull-anchor effect, the soil between the piles together has a gravity effect, and the alternating arrangement of piles has a spatial structure effect. The three major effects increase the stiffness and stability of the support structure, which is conducive to the deformation control of the foundation pit. The research results will provide a theoretical basis for the popularization and application of the structure.

来源平台：MECHANICS OF ADVANCED MATERIALS AND STRUCTURES