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.

Wind energy offers significant advantages over fossil fuels, including extensive energy storage and environmental sustainability. Offshore wind turbines serve as the primary technology for harnessing offshore wind power. However, the corrosive effects of the marine environment pose serious threats to their safety and stability. This paper provides a comprehensive overview of corrosion issues affecting steel pipe pile infrastructure, focusing on the following key aspects: (1) Differentiating corrosion mechanisms under various environmental conditions, (2) analyzing the comprehensive corrosion response, particularly the changes in mechanical properties of the pile-soil interface and the bearing capacity of steel pile foundations, (3) summarizing the patterns and trends in corrosion processes to offer theoretical insights for engineering design, and (4) reviewing commonly employed corrosion prevention methods and their respective applicability in relation to specific corrosion mechanisms and responses.