International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 05 | May 2025
p-ISSN: 2395-0072
www.irjet.net
Experimental Study on Pullout Capacity of Helical Piles Embedded in Homogenous and Layered Sand Bed Shashidhara E1, Virancha M2, K.V.S.B Raju3 1Post graduate student, Dept. of Civil Engineering, UVCE College (University), Bengaluru
2 Post graduate student, Dept. of Civil Engineering, UVCE College (University), Bengaluru 3Associate Professor, Dept. of Civil Engineering, UVCE College (University), Karnataka, India-560056
---------------------------------------------------------------------***--------------------------------------------------------------------loading remains essential. In particular, the effects of soil Abstract - Helical piles have emerged as a reliable deep density and load angle on pullout resistance need deeper foundation solution in geotechnical engineering, prized for investigation. This study addresses these gaps by their ease of installation and superior performance under experimentally analyzing helical piles in varied sand uplift and tensile loads. This study presents an experimental conditions. The findings aim to inform better, more reliable investigation into the axial and oblique pullout behavior of foundation designs for real-world applications. helical piles embedded in both homogeneous and layered sand beds. The primary aim is to assess how key parameters—such 1.1 History of Helical Piles as sand relative density, number of helices, helix spacing ratio (S/Dh), and loading angle influence uplift performance. A total The use of helical piles, or “screw piles,” dates back to the of 54 small-scale model tests were conducted on monopiles 1830s when Alexander Mitchell, an English brick maker, and helical piles with one, two, and three plates, embedded in patented the design in 1833. He first applied it successfully in dry sand at relative densities of 30% and 60%. Tests were also the foundation of the Maplin Sands Lighthouse, constructed carried out in layered profiles consisting of a loose upper layer on unstable ground near the River Thames. The foundation over a denser lower layer. Load inclination angles of 0°, 30°, featured cast iron helices and wrought iron shafts arranged in and 45° were applied to simulate axial and oblique pullout an octagonal layout, manually installed to a depth of 6.7 scenarios. The results show that pullout capacity increases meters. Mitchell’s 1848 paper, On Submarine Foundations, with higher relative density, more helices, and greater was the first technical publication on screw piles, highlighting embedment depth. Multi-helix piles performed significantly their ability to resist both vertical and uplift forces. Modern better when helix spacing reduced plate interaction, research gained momentum from 2003 to 2005 with the particularly at S/Dh = 3. Beyond this spacing, gains in capacity introduction of finite element modeling, which helped reduce were marginal, indicating a shift from cylindrical shear to costs and advance design methods. Between 2012 and 2020, individual plate bearing. Layered soils offered improved uplift global studies explored the influence of material types, configurations, and soil conditions on pile performance. resistance due to the confining effect of the denser layer. These Recent investigations have focused on lateral capacity, group findings provide experimental validation for theoretical behavior, and offshore applications, underscoring the models and offer practical insights for optimizing helical pile growing importance of helical piles in contemporary design in uplift-critical applications. geotechnical engineering. Key Words: Helical Pile, Pullout Capacity, Oblique 1.2 Advantages of Helical Piles Loading, Relative Density, Inter-Helix Spacing, Individual Plate Bearing, Cylindrical Shear, Helical piles offer a versatile and efficient foundation Homogenous, Sand Bed. solution suitable for a wide range of soil conditions, including soft, loose, or waterlogged soils. Their quick 1. INTRODUCTION installation process requires minimal excavation and equipment, reducing time, cost, and site disruption In civil engineering, many structures such as transmission especially valuable in urban or restricted-access areas. With towers, solar panels, and tall chimneys require foundations low noise and vibration during installation, they are ideal for capable of resisting significant uplift forces. Traditional environmentally or noise-sensitive sites. Helical piles footings often fall short under such tension, prompting the provide immediate load-bearing capacity, allowing faster need for more efficient solutions. Helical piles have emerged project timelines. They are available in various sizes and as a cost-effective and sustainable alternative, offering quick configurations to meet different load and site requirements installation and minimal environmental disruption. These and offer excellent resistance to both vertical and uplift deep foundation systems are especially suited for resisting forces, making them suitable for structures exposed to wind, pull-out loads due to their screw-like geometry. Enhancing seismic, or flood loads. Additionally, they can be easily the surrounding soil can further improve their performance removed, reused, or extended, contributing to sustainable under uplift. While their use is expanding, a comprehensive and cost-effective construction practices. understanding of their behavior under axial and inclined
© 2025, IRJET
|
Impact Factor value: 8.315
|
ISO 9001:2008 Certified Journal
|
Page 1766