Faculty Publications
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Item Effect of geosynthetic stiffness on the behaviour of encased stone columns installed in lithomargic clay(Springer, 2020) Vibhoosha, M.P.; Bhasi, A.; Nayak, S.Columnar systems have been extensively used to support structures on problematic ground conditions. Encased stone columns are very effective for flexible structures such as embankments and storage tanks where a relatively large settlement is permissible. Lithomargic clay is extensively found along the Konkan belt in peninsular India and serves as the foundation for most of the structures. Construction activities in lithomargic clays are challenging due to the fact that there occurs drastic reduction in strength under saturated conditions. In this paper, the effectiveness of encased stone column in lithomargic clay has been studied and a 3D column model was developed to examine the effect of geosynthetic stiffness on the column-load-carrying capacity. © Springer Nature Singapore Pte Ltd. 2020.Item Performance Evaluation of Stone Column Reinforced Shedi Soil(Springer Science and Business Media Deutschland GmbH, 2024) Vibhoosha, M.P.; Bhasi, A.; Nayak, S.Ground modification techniques are adequate in the present scenario, due to the scarcity of suitable construction sites. The problematic soil widespread in the Konkan region of west coast India is shedi soil. Construction over this soil is challenging because it loses strength when saturated. Among the various ground modification techniques, the use of stone columns is an ideal technique due to their higher strength and stiffness properties compared to the surrounding soft soil. The cost effectiveness and ease of installation make stone column method popular in India. In the present paper, the performance of stone column reinforced shedi soil is analysed, by developing a three-dimensional finite element model in ABAQUS. The long-term stability is imparted with the time-dependent behaviour and it is evaluated. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Effect of Column Configuration on the Performance of Encased Stone Columns with Basal Geogrid Installed in Lithomargic Clay(Springer, 2019) Nayak, S.; Vibhoosha, M.P.; Bhasi, A.Lithomargic clay is extensively found along the Konkan belt in peninsular India and serves as a foundation for most of the structures. The reduction in strength under saturated conditions makes this soil problematic causing a lot of engineering problems such as uneven settlements, erosion, slope failures, and foundation problems. This paper presents the effect of column configuration (i.e. equivalent number of columns with reduced diameter for the same surface area) on the performance of lithomargic clay reinforced with geogrid encased stone columns and basal geogrid layer. The investigations were performed both experimentally through small-scale models and through finite element analyses. The results were compared with the performance of lithomargic clay reinforced with ordinary and encased stone columns. A single geogrid encased stone column with a basal geogrid layer improved the load-carrying capacity of lithomargic clay by 180% while the percentage of increment in the case of a group of three geogrid encased stone column with basal geogrid layer having the same surface area was 210%. It was also observed that the geogrid encasement of stone columns reduced the maximum column bulging by 38%, whereas geogrid encased stone columns along with basal geogrid layer reduced the bulging by 82% compared to ordinary stone columns. © 2019, Springer Nature Switzerland AG.Item Analysis of Geocell-Reinforced Stone Column-Supported Embankment Considering Soil-Structure Interaction(Springer, 2022) Vibhoosha, M.P.; Bhasi, A.; Nayak, S.Geocells are a superior form of reinforcement due to their cost-effectiveness and three-dimensional confining properties. The effect of the basal geocell layer on the performance of the stone column-supported embankment was evaluated in this paper by carrying out time-dependent coupled analyses considering the geocell-infill soil interactions. The various parameters, such as arching, stress concentration ratio, surface settlement, column bulging characteristics, and the influence of various types of infill materials and drainage blanket thickness on column-supported embankment behavior, were analyzed. The load transfer mechanism was quantified using the term stress concentration ratio, and with the use of geocell mattress above stone columns, the stress concentration ratio increased by 1.5 times that of ordinary stone columns. Also, it was observed that compared to ordinary stone column-supported embankment, the combination of stone columns with geocell-sand mattress resulted in a further reduction of the foundation settlement by 15%. Analysis results showed that the arching behavior is not predominant in geocell-reinforced columnar structures. The various analytical methods like Guido et al. (1987), Low et al. (1994), and Abusharar et al. (2009), which were developed for geosynthetic reinforced columnar embankments, were found to significantly under-predict the stress reduction ratio values with geocells. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.