Faculty Publications
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Item Comparative study on bearing capacity of bottom ash-stabilized soil mixed with natural and synthetic fibers(ASTM International service@astm.org, 2020) Prasannan, S.; Kolathayar, S.; Sharma, A.K.This article assesses the strength behavior of bottom ash (BA)-stabilized soil mixed with different fibers through a series of laboratory tests. Optimum BA and fiber percentage were obtained by small scale lab tests like compaction tests and unconfined compressive strength (UCS) tests. From compaction tests with varying proportions of BA (10, 20, 30, and 40 %), the optimum BA content was found to be 30 %. With this optimum BA content, UCS tests were conducted on soil-BA mix with different fibers (coir, areca, sisal, and polyvinyl alcohol) at various percentages (0.5, 1, 1.5, and 2 %) to find the optimum fiber content. A set of model footing tests were done to check the credibility of using fibers as a strengthening material beneath footing to upgrade the engineering properties of soil to make a reasonable subsoil for the foundation. A total of six model footing tests were performed on raw soil, on soil with optimum BA content, and on BA-stabilized soil mixed with different fibers in their optimum percentage (1.5 %). The bearing capacity of unstabilized unreinforced soil was found to increase significantly with the inclusion of fibers. © © 2020 by ASTM InternationalItem Performance of Footing on Clay Bed Reinforced with Coir Cell Networks(American Society of Civil Engineers (ASCE) onlinejls@asce.org 1801 Alexander Bell DriveGEO Reston VA 20191 Alabama, 2020) Kolathayar, S.; Narasimhan, S.; Kamaludeen, R.; Sitharam, T.G.Geocells are three-dimensional polymeric hexagonal pockets that provide lateral confinement to the soil, thereby increasing the bearing capacity of the soil bed. This paper briefly reviews past studies on geocell reinforcement of soil and presents a new product, cells made out of natural coir fiber, as an alternative to commercially available high-density polyethylene (HDPE) geocells. A series of model plate load tests were conducted on unreinforced soil and on soil reinforced with coir geocells to understand the soil reinforcement mechanism. It was observed that with the introduction of coir geocells, the load-bearing capacity of the soil bed increased up to three times and a significant reduction in the settlement was observed in the underlying weak soil bed. The study also presents a comparative performance evaluation of the natural coir cell-reinforced soil with conventional HDPE geocell-reinforced soil. Further, this paper analytically demonstrates the influence of the lateral resistance effect and vertical load dispersion effect incorporated by coir cells in strengthening the soil bed. © 2020 American Society of Civil Engineers.Item Model Footing Tests and Analytical Studies on Clayey Soil Bed Reinforced with Coconut Shell Mat(Springer Science and Business Media Deutschland GmbH, 2022) Kolathayar, S.; Gadekari, R.S.The cellular confinement systems are becoming popular in ground improvement because of their efficiency in improving the bearing capacity of soil due to the lateral confinement effect. The commercially available geocells are made from polymer materials and they are costly. This study presents the performance evaluation of coconut shell mat as a cellular confinement system in clayey soil. It is the first of its kind application of coconut shells for soil reinforcement through a lateral confinement mechanism. This soil reinforcement system using coconut shells is termed “Geococoshell” by the authors. A series of model plate load tests were conducted on unreinforced soil, soil reinforced with High-Density Polyethylene (HDPE) geocells, and soil reinforced with coconut shell mats to evaluate the performance of coconut shell mat reinforced soil bed. The results of the experiments showed that coconut shells reinforced clayey soil improved bearing capacity up to 1.5 times compared to HDPE geocell reinforced clayey bed. The effect of different patterns of placing coconut shell mat was also studied and discussed in the paper. The analytical studies have been conducted considering the reinforcement mechanisms of coconut shell mat embedded in the soil bed. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.Item Performance Evaluation of Jute Geocell-Reinforced Sand Subgrade with an Integrated Wooden Anchor Grid(Springer Science and Business Media Deutschland GmbH, 2025) Kumar, P.; Kumar, D.H.; Bandyopadhyay, T.S.; Raveendran, D.; Kolathayar, S.; Mulangi, R.H.The efficient confinement capabilities of geocells make them a popular reinforcement technique for improving soil stability and load-bearing capacity. However, the high costs of synthetic geocells and environmental concerns have driven interest in more sustainable and natural alternatives. This study presents a novel approach to subgrade reinforcement using a jute geocell (JG) made from jute fabric, further improved with a wooden anchor grid (WAG). The newly developed jute geocell with wooden anchor grid (JGWAG) consists of a natural wooden grid integrated with anchor pins placed at the center of each JG pocket, aiming to enhance load-bearing capacity. The effectiveness of this innovative reinforcement system was evaluated through static plate load tests on sand subgrade reinforced with JG mattresses of varying widths (1.33D, 2D, and 3.33D, where D is the loading plate diameter) and a WAG placed beneath the 2D-width geocell. The results demonstrated significant performance enhancements: load-bearing capacity increased by 41%, 83.8%, and 116% for 1.33D, 2D, and 3.33D, respectively, compared to unreinforced subgrade. Notably, adding WAG under the 2D-width geocell achieved a remarkable 186% improvement over the unreinforced case. Settlement reduction was also significant, with the JGWAG system decreasing settlement by 84.6% as compared to the unreinforced case, showcasing its superior effectiveness. This system improves load-bearing performance and provides a cost-effective solution by reducing the width of JG. Furthermore, the surface roughness of the JG was analyzed using a 3D surface profilometer, ensuring optimal contact and friction between the soil and reinforcement for improved load transfer. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.