In an era where climate change intensifies the frequency and severity of natural disasters such as typhoons and tornadoes, the stability of tall infrastructure under extreme wind conditions is more critical than ever. Towers that support telecommunications, transmission lines, and solar panels confront the challenge of severe uplift forces that threaten the integrity of their foundations. Conventional approaches primarily address compressive loads; however, uplift forces demand novel foundation technologies capable of withstanding these dynamic stresses. Simultaneously, the construction industry grapples with the persistent issue of surplus excavated soil—the costly and environmentally taxing byproduct of earthworks that often ends up in landfills or distant disposal sites. Addressing these intersecting challenges, researchers at the Shibaura Institute of Technology (SIT) in Japan have pioneered an innovative winged composite pile foundation system that not only resists wind-induced uplift effectively but also repurposes surplus construction soil as a vital structural component.
Led by Professor Shinya Inazumi, the research team embarked on an extensive study to design and test a foundational solution integrating steel structural elements with locally sourced surplus soil to enhance uplift resistance. This solution aims to diminish reliance on imported backfill materials, reduce environmental impact, and provide robust uplift capacity without compromising sustainability. The cornerstone of this system lies in a composite pile: a steel pipe augmented with expanded base wings and surrounded by steel structural elements, enclosing an annular space densely packed with excavated soil from the construction site itself. This approach leverages the previously underutilized surplus soil as an integral mechanical element, transforming waste into value within the geotechnical framework.
To rigorously assess the uplift resistance, the team conducted 35 model-scale uplift experiments encompassing seven distinct pile configurations. These experiments systematically varied parameters such as the diameter of the base wings, soil compaction levels, steel surface finishes, and the presence or absence of corrugated liner plates encasing the soil core. The inclusion of corrugated liners was motivated by the hypothesis that surface texture would directly influence frictional interaction and mechanical interlocking at the soil-steel interface, factors crucial for resisting uplift. Complementing the physical testing, finite element method (FEM) simulations were developed to predict performance trends and validate experimental observations, confirming that numerical modeling could effectively mirror complex soil-structure interactions.
A pivotal discovery was the demonstrable correlation between the diameter of the expanded base wings and uplift capacity. Larger wing diameters consistently delivered increased resistance across all soil densities and pile variants tested. This reinforced the premise that geometric modifications of the pile base substantially influence uplift performance, providing engineers with a controllable design parameter to optimize foundations for high-wind environments. Impressively, winged composite piles filled with surplus soil matched or even exceeded the uplift strengths of traditional steel pipe piles, validating the concept of soil reuse as a feasible enhancement rather than a compromise.
Soil density emerged as another critical determinant of uplift resistance. Results indicated that a 20% decrease in soil compaction led to an approximately 50% drop in uplift capacity. This underscored the necessity of rigorous compaction protocols during site preparation to ensure structural integrity. It further accentuated the dual role of surplus soil as both a material resource and a variable requiring careful quality control, blending geotechnical expertise with sustainable practices.
The study also revealed that the micro-texture of steel surfaces impacts uplift forces. Corrugated liner plates enhanced resistance by around 12-13% compared to smooth steel surfaces, a finding attributable to improved soil adhesion through increased friction and mechanical interlocking effects. This nuanced interplay between structural surface design and soil mechanics highlights how minor engineering adaptations can yield disproportionate benefits in foundation performance.
Professor Inazumi emphasized the practical implications of these discoveries, remarking that the winged composite pile system offers a compelling foundation alternative for infrastructures subjected to wind uplift on sandy soils, common in many regions. Such applications include solar power farms, telecommunication towers, radio masts, and transmission lines. The approach promises not only structural reliability but also significant reductions in environmental footprint and project costs by minimizing the need for importation of specialty backfill materials.
Interpreting the research findings into actionable engineering guidelines, the team formulated design recommendations that relate uplift resistance to wing geometry and soil compaction. These guidelines aim to standardize implementation, providing architects, engineers, and construction managers with data-driven insights to optimize foundation design in windy climates. The analysis confirms that winged piles with soil-filled annuli represent a transformative step in geotechnical engineering, combining resilience, sustainability, and economic pragmatism.
The fusion of experimental investigations and FEM analyses underscores the maturity and reliability of this novel method. As infrastructure resilience becomes paramount amid escalating environmental challenges, the research from SIT pioneers a shift towards smarter, circular construction methodologies where waste is consciously reintegrated within structural designs. This paradigm not only enhances safety but also aligns with global initiatives prioritizing resource efficiency and carbon footprint reduction in the built environment.
Beyond its immediate applications, this innovation sets a precedent for reevaluating how surplus construction materials are perceived and utilized. Traditionally regarded as liabilities, these soils now form part of an active solution, elevating site-specific materials to functional constituents in load-bearing systems. The research advocates a holistic viewpoint, integrating material science, structural engineering, and environmental stewardship within modern construction workflows.
Ultimately, the winged composite pile system embodies the convergence of technical advancement and sustainable development. By transforming surplus soil into a pillar of strength against wind-induced uplift, it charts a course for resilient infrastructure amidst climatic uncertainty. As such, it is poised to influence construction practices worldwide, advocating for foundations that are as eco-conscious as they are robust.
Subject of Research: Not explicitly specified beyond foundation engineering and uplift resistance study.
Article Title: Uplift resistance of winged composite piles with surplus soil backfill: Model experiments and numerical validation
News Publication Date: March 1, 2026
Web References:
References:
- DOI: 10.1016/j.rineng.2026.109404
Image Credits:
Credit: Professor Shinya Inazumi, Shibaura Institute of Technology, Japan
Keywords
Applied sciences and engineering, Engineering, Civil engineering, Construction engineering, Man made structures, Structural engineering, Urban planning
