Ground Improvement Techniques for Problematic Soils: A Review of Stone Columns and Granular Anchor Piles

Abstract

Construction on problematic soils, including loose sands, soft clays, expansive soils, and collapsible soils, poses significant challenges that can affect the stability, durability, and economic feasibility of structures. Such soils often exhibit inadequate strength and poor load-bearing capacity, which can result in issues such as excessive settlement, differential settlement, slope instability, and, in extreme cases, structural failure. To mitigate these risks, various ground improvement techniques have been developed to enhance the engineering properties of weak soils, ensuring that they can safely support structural loads. Ground improvement methods are crucial in modifying soil characteristics to increase its strength, reduce compressibility, and improve overall stability. These techniques can be broadly classified into mechanical, chemical, and inclusions-based methods. Mechanical methods, such as compaction and vibroflotation, enhance soil density. Inclusions, such as stone columns and granular anchor piles, provide reinforcement by replacing or mixing weak soils with stronger granular materials, increasing their strength and stiffness. Among these approaches, stone columns and granular anchor piles have proven highly effective in stabilizing weak soils and improving their load-bearing capabilities. Stone columns function by redistributing loads, accelerating consolidation, and enhancing drainage, making them particularly useful in soft clay and loose sand conditions. Granular anchor piles, on the other hand, provide additional anchorage and confinement, preventing excessive deformation and settlement. This review explores the characteristics of problematic soils, highlights the importance of ground improvement, and examines the role of stone columns and granular anchor piles in addressing foundation-related challenges.

Introduction

Problematic soils—such as soft clays, silts, loose sands, expansive soils, and peat—pose significant challenges for construction due to low strength, high compressibility, swelling/shrinking behavior, and poor load-bearing capacity. These soils can cause foundation instability, excessive settlement, and structural damage.

Key issues include:

• Expansive clays: Swell when wet and shrink when dry, leading to heaving and cracking of foundations. Mitigation often requires special foundation designs like piles or raft foundations.

• Soil liquefaction: Occurs in loose saturated granular soils during seismic shaking, causing loss of soil strength and resulting in ground failures such as lateral spreading, flow failures, and reduced pile capacity.

• Peat soils: Highly compressible, with low shear strength and high moisture content, making them unsuitable for construction. Innovative treatments like vegetable-based grout can significantly increase peat soil strength.

To improve these challenging soils, ground improvement techniques such as stone columns (replacing weak soil with compacted gravel) and granular anchor piles (piles filled with granular material to resist uplift) are widely used. These methods enhance soil strength, reduce settlement, improve drainage, and provide stability in weak or expansive soils, offering cost-effective solutions for difficult geotechnical conditions.

Conclusion

The following conclusions from the review of the problematic soils, stone column, granular anchor pile; 1) The installation of granular pile anchors (GPAs) in expansive soils significantly reduces the time required for heave, leading to an accelerated rate of heave. Expansive soils reinforced with GPAs adapt more quickly to moisture changes due to the high permeability of the granular material. This permeability facilitates faster water circulation and absorption, thereby shortening the radial inflow path and enabling quicker attainment of the final heave. The time required to achieve final heave in GPA-reinforced soil is approximately three-sevenths of that for unreinforced expansive soil. 2) The observed heave decreased significantly when the clay bed was reinforced with granular pile anchors (GPAs). The reduction in heave ranged from 43% to 93%, depending on the diameter and length of the GPA. These results demonstrate that GPAs are an effective solution for controlling heave in shallow foundations constructed on expansive soils. 3) The ultimate pullout load of an encased pile is greater than that of a non-encased pile. 4) Additionally, as the size of the granular material increases, resistance to uplift load improves. This improvement is attributed to the formation of a larger pressure bulb in soils containing larger aggregates compared to soils with smaller aggregates. 5) The GPA system is a cost-effective foundation technique suitable for various soil types. It effectively counters uplift forces and minimizes heave. Field and laboratory studies suggest that the performance of the GPA system is comparable to or even superior to traditional tension-resistant foundation methods, such as concrete anchor piles and screw piles. Compression tests indicate that the GPA system exhibits behavior similar to a standard stone column in soft soils. 6) The ultimate uplift capacity of the GPA depends on its embedment ratio (length-to-diameter ratio), the relative density and elastic modulus of the surrounding soil and GPA material, the water table level, and the degree of saturation of the surrounding soil.

References

[1] Arghadeep Biswas; Experimental Study on Parametric Influences of Stone Column Reinforced Foundation Systems” [2] Aravind M “Applicability Analysis of Stone Column Against Liquefaction Under Repeated Dynamic Events. [3] Amees Mushtaq, Pullout Capacity of Piles in Unsaturated High Plasticity Clayey Soil: An Experimental Model Study” Journal of Civil Engineering. [4] Adamu Beyene, Ruhama Beyene, Hailemariam Merka (2024) Sensitivity of granular pile dimension parameters to deformation response of soft ground under building load. Applications in Engineering Science 17 100169. [5] Alvin John Lim Meng Siang (2020) Ground improvement using granular pile anchor system: resistance to heave and uplift pressure. Indonesian Journal of Electrical Engineering and Computer Science Vol. 19, No. 1, pp. 403~411 [6] Awdhesh Kumar Choudhary1 and Sujit Kumar Dash2 Pullout behaviour of vertical plate anchor in granular soil. [7] S. Athani, P. Kharel, D. Airey and P. Rognon (2017) Grain-size effect on uplift capacity of plate anchors in coarse granular soils. Géotechnique Letters 7 [8] Behnam Bagheri (2024) Pullout Capacity of Long Granular Pile Anchors Using Numerical Analyses of Random Fields. Journal of Civil Engineering 28(10):4214-4229 [9] Carlos Lama,n , Stephan A. Jefferisb Effects of polymer and bentonite support fluids on the performance of bored piles. Soils and Foundations. [10] Farah Atiqah Abdul Azam (2024) Mechanical behavior, compressibility, and microstructural analysis of problematic soil through a green soil stabilization approach. Results in Engineering 24 103524 [11] FukunGui1,3, Jianqiao Kong1,3, Dejun Feng1, Xiaoyu Qu2*, Fang Zhu1 & YangYou1 (2021) uplift resistance capacity of anchor piles used in marine aquaculture. Scientifc Reports 11:20321 [12] Geever Alwin Ambadan, Shankar Kandasamy, Ganesh Kumar S, B Effectiveness of Geosynthetic Encased Stone Column Technique for Liquefaction Mitigation. [13] Heena Malhotra (2020) Ground Improvement by Granular Anchor Pile Foundation in Cohesive Soil under Axial Pull-Out Loads. Proceedings of Indian Geotechnical Conference [14] Hans Raj Vashishtha and Vishwas A. Sawan (2021) An experimental investigation for pullout response of a single granular pile anchor in clayey soil. Vashishtha and Sawant Geo-Engineering 12:35 [15] Haroon Ali Khan1, Kalpana Gaddam2 (2021) An Experimental Study on heave and Uplift Behaviour of Granular Pile Anchor Foundation System. IOP Conf. Series: Earth and Environmental Science 822 012038 [16] Jun AI (2013) The role of deposition process on pressure dip formation underneath a granular pile. Mechanics of Materials 66 160–171 [17] Kiyoshi Kishida (2016) Discussion on the mechanism of ground improvement method at the excavation of shallow overburden tunnel in difficult ground. Underground Space 1 94–107 [18] Koki Nakao (2021) Visual evaluation of relative deep mixing method type of ground-improvement method Results in Engineering 10 100233. [19] Koushik Pandit (2020) Ground Improvement of a Liquefiable Soil by Granular Piles. Proceedings of Indian Geotechnical Conference [20] A. Kranthikumar1 V. A. Sawant1 S. K. Shukla (2016) Numerical Modeling of Granular Anchor Pile System in Loose Sandy Soil Subjected to Uplift Loadingnt. J. of Geosynth. and Ground Eng. 2:15 [21] Lubna Amayreh Engineering properties and mechanical behaviour of problematic soil stabilized by bituminous oil shale ash. Applications in Engineering Science. [22] Luca Masini, (2025) Effect of soil improvement on ground movements induced by conventional tunnelling. Tunnelling and Underground Space Technology 155 106163 [23] Mohammad Javad Rezaei-Hosseinabad (2022) Sustainable utilisation of steel slag as granular column for ground improvement in geotechnical projects. Case Studies in Construction Materials 17 e01333 [24] Manita Das1 and Ashim Kanti Dey2 Improvement of Bearing Capacity of Stone Columns. An Analytical Study [25] Neenu Johnsona, M.N.Sandeep (2016) Ground Improvement Using Granular Pile Anchor Foundation. Procedia Technology 24 263 – 270 [26] Omed Azeez1, Rizgar Hummadi1, Ahmed Hasan1 (2019) Ultimate capacity of laterally loaded pile foundation in dry and saturated layered soils. international Journal of Engineering Research and Technology. ISSN 0974-3154, Volume 12, Number 10 [27] Osama Nusier, Ahmed Alawneh, Ahmad Alsuqaier (2023) The efficiency of granular pile anchor foundation system in reducing heave of Irbid expansive clayey soil experimental investigation. Case Studies in Construction Materials 18 e01846 [28] Priti Maheshwari1, J. P. Sahoo2 and Siddhartha Saxena3 (2020) Settlement of a Square Footing on Dry Sand Bed Reinforced with Stone Columns under Seismic Conditions: effect of Frequency. Proceedings of Indian Geotechnical Conference [29] PILES N. Sabhahiti, P. K. Basudharii, Generalized Stability Analysis of Embankments on Granular. Soils and Foundations Vol. 37, No.4 [30] B. R. Phanikumar1, Ammavajjala Sesha Sai Raghuram2 Expansive clay beds through granular pile-anchors and geogrid encased granular pile-anchors. Proceedings of the Institution of Civil Engineers Ground Improvement [31] Rathod Numerical study of granular anchor pile subjected to uplift load. [32] Saad F. Ibrahim1, Ala Nasir Aljorany2 (2014) Heave Behavior of Granular Pile Anchor-Foundation (GPA-Foundation) System in Expansive Soil. Journal of Civil Engineering and Urbanism Volume 4, Issue 3: 213-222 [33] Sareesh Chandrawanshi (2020) Settlement Behaviour of Very Soft Soil Reinforced with Stone Columns. Proceedings of Indian Geotechnical Conference [34] Satish Barmade1 Vinayak Kale2 (2020) Experimental Study on Load Settlement Behaviour of Granular Stone Column in Expansive Soil. Proceedings of Indian Geotechnical Conference [35] Sudip Basack1, Buddhima Indraratna1 and Cholachat Rujikiatkamjorn (2016) Analysis of the Behaviour of Stone Column Stabilized Soft Ground Supporting Transport Infrastructure. Advances in Transportation Geotechnics. The 3rd International Conference on Transportation Geotechnics [36] Takayuki Sakai (2023) Improvement in seismic resistance using replacement/counterweight f ill method for existing high embankments on inclined ground constructed with various embankment materials. Soils and Foundations 63 101284 [37] Terunori Iriea,Ryusei Yamaguchi (2022) History-dependent deformation of a rotated granular pile governed by granular friction” Advanced Powder Technology 33 103629 [38] A.Vittalaiah1, E.C.Nirmala Peter2 and Rathod Ravinder3 (2020) Improvement of Soft Clays Using Stone Columns With And Without Encasement. Proceedings of Indian Geotechnical Conference [39] wing Masatoshi Wada a, Kohji Tokimatsu (2017) Effects of cyclic vertical loading on bearing and pullout capacities of piles with continuous helix. Soils and Foundations 57 141–153 [40] Yuan Cheng (2017) Experimental research of spatial variation of compaction effect on vibratory probe compaction method for ground improvement. Procedia Engineering 189 466 – 471 [41] Tatsuro Muroi), Munehito Miyoshiii, Takahiro Mitsubayashii (1998) Effect of A Tracked Vehicle Mounting an Oscillator on The Vibro-Compaction of A High Lifted Decomposed Granite Sandy Soil. Soils And Foundations Vol. 38, No.4, 129-144 [42] Guojun Cai, Jun Lin, Songyu Liu, Anand J. Puppala (2017) Characterization of Spatial Variability of Cptu Data in A Liquefaction Site Improved by Vibro-Compaction Method. Journal Of Civil Engineering 21(1):209-219 [43] Chuanxun Li?, Xiangzong Lu, Peng Wang (2023) An Analytical Solution for The Consolidation of a Composite Foundation Reinforced by Vertical Drains and High Replacement Ratio Gravel Piles by Considering The Radial Flow Within Gravel Piles. Soils And Foundations 63 101393 [44] Zhichao Shena, Siau Chen Chianb, Siew Ann Tanb, Chun Fai Leungb(2024) Modelling Smear Effect Of Vertical Drains Using A Diameter Reduction Method. Journal Of Rock Mechanics and Geotechnical Engineering 16 (279e2900.

Copyright

Copyright © 2025 Dinesh Maruthu M, Chithra S. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.