Mechanical Performance and Landslide Stabilization Applications of Precast Small-Diameter Prestressed Concrete Pipe Piles

Ming Wu¹Yao Liang²Xiaobo Tang^2*

• ¹Shu Dao Financial leasing(Shenzhen) CO., LTD, Guangdong Shenzhen, China
• ²Sichuan Shuxin Lianchuang Technology Co., LTD, Sichuan Chengdu, China

This study presents a comprehensive material-oriented investigation into the mechanical enhancement and efficiency optimization of precast prestressed concrete pipe (PPCP) piles for landslide stabilization. Through an integrated approach combining material performance tests and geometrically scaled physical models, we systematically evaluate the structural and functional superiority of core-filled PPCPs compared to conventional hollow sections, with emphasis on material compounding effects, crack resistance, and deformation control. The core-filled pile design utilizes an external high-strength prestressed concrete shell infilled with C40 expansive self-compacting concrete, forming a composite section that significantly improves material utilization and mechanical performance. Quantitative results demonstrate that the core-filled configuration enhances crack initiation load by 21.9%, increases crack resistance moment by 24.0%, and reduces vertical deformation by 17–22% during the elastoplastic stage relative to hollow piles. Core-filled PPCPs exhibit a 32.6% higher shear strength than hollow piles, further validating their structural superiority in landslide stabilization. This performance gain is attributed to the synergistic interaction between the prestressed shell and the infill material, which effectively confines tensile cracking, suppresses diagonal shear crack propagation, and promotes more uniform stress redistribution across the pile section. Material-level consistency is confirmed, with variations in cracking and ultimate moments limited to 3.3–4.3% and 1.6–8.9%, respectively, ensuring reliability in engineering applications. All model tests were conducted under a soil saturation of 85%, simulating the typical moist condition of slopes in southwest China. In 1:12 scale landslide model tests designed based on similarity theory, the composite pile-slope system exhibits consistent three-stage mechanical behavior, with the critical load averaging 45% of the ultimate load, corresponding to a structural safety factor of 2.2. Optimized pile arrangements—particularly single-row layouts in two-tier slopes and double-row systems with 4D spacing—further enhance load transfer efficiency and soil–pile interaction, leading to higher ultimate load capacities with reduced material demand per unit stabilizing effect. The study elucidates how material compounding and sectional optimization can alter failure modes, restrain slip surface penetration, and improve overall system ductility.