Comparative Analysis of Helical Piles and Granular Anchor Piles for Foundation Stabilization in Expansive Soil: A 3D Numerical Study

Abstract

This study investigates the performance of granular anchor piles and helical piles in expansive soils. Expansive soils pose challenges for engineering due to their significant swelling and shrinkage characteristics. Special considerations are required for constructing foundations on expansive soil to mitigate volumetric changes. While helical piles provide uplift resistance in light structures, they may not fully stabilize foundations in expansive soils. In contrast, granular anchor piles offer a simpler alternative for resisting uplift forces. A numerical study was conducted to analyze the pullout loads, compressive loads, and heave behavior of these anchor techniques. The results demonstrate that granular anchor piles outperform helical piles in terms of pullout and compressive performance, with improvements ranging from 17% to 22.5% in pullout capacity and 0.5% to 19% in compressive capacity, depending on specific pile lengths and diameters examined. However, both techniques show similar effectiveness in reducing heave, achieving reductions of over 90% when specific conditions are met. Additionally, the use of high-rise cap piles contributes to significant heave reduction, effectively minimizing heave to nearly negligible levels compared to low-rise cap piles. It is found that the relative density of the granular material has a more pronounced effect on the pullout load compared to the compressive load, and its impact varies depending on the length of the pile. Therefore, it is recommended to avoid high relative density when the pile is entirely within the expansive soil while utilizing higher relative density is beneficial when the pile penetrates and settles in the stable zone.

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“…The present study follows a methodology similar to that of Alnmr et al [94,95]. Figure 15 provides a cross-sectional view of reinforced soil featuring helical piles.…”

Experimental Investigation of the Soil-Water Characteristic Curves (SWCC) of Expansive Soil: Effects of Sand Content, Initial Saturation, and Initial Dry Unit Weight

“…The primary application of the soil-water characteristic curve (SWCC) is to evaluate the performance of unsaturated soil properties for a range of geotechnical engineering applications [1]. One common application of SWCCs in geotechnical engineering is to assess the hydraulic properties necessary to simulate water flow through unsaturated soils [2][3][4][5][6]. The SWCC shape reflects the soil's water retention capacity and porosity characteristics, enabling the estimation of various engineering properties such as hydraulic conductivity, shear strength, and diffusion coefficient [7,8].…”

Novel Insights in Soil Mechanics: Integrating Experimental Investigation with Machine Learning for Unconfined Compression Parameter Prediction of Expansive Soil

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