Journal Articles
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884
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Item Numerical Investigation of Consolidation Induced by Prefabricated Horizontal Drains (PHD) in Clayey Deposits(Springer Science and Business Media Deutschland GmbH, 2021) Menon, A.R.; Bhasi, A.In this work, the process of prefabricated horizontal drains (PHD) induced consolidation in clayey embankment fills is investigated by a numerical approach. Based on spacing parameters, the suitability of axisymmetric and plane strain conditions for modeling the drain has been studied, and the suitability zones and matching functions have been proposed. The implications of the use of elastoplastic models to simulate the behavior of in situ soil on the suitability zones and matching functions have also been studied. The numerical results were compared with the analytical unit cell solutions for axisymmetric and plane strain conditions. Further, the effect of PHD in improving the consolidation behavior of various soil types has been analyzed in terms of pore pressure dissipation and settlement. The studies showed that the drain improved ground is best modeled under axisymmetric conditions at lower spacing ratios, and plane strain conditions simulate the more distantly spaced cases. PHD was found to accelerate the consolidation process in soft soils significantly, and the effect was found to be most prominent in highly plastic soils. © 2020, Springer Nature Switzerland AG.Item Three dimensional analyses of geocell reinforced encased stone column supported embankments on lithomargic clay(Taylor and Francis Ltd., 2023) Vibhoosha, M.P.; Bhasi, A.; Nayak, S.Geocells are a superior form of reinforcement due to their cost-effectiveness and three-dimensional confining properties. However, numerical modeling of geocell is always challenging due to its three-dimensional honeycomb structure. The limitations of the equivalent composite approach (ECA) led to the recent development of full 3D numerical models, which consider geocell-infill material interaction. This paper discusses the time-dependent performance of geocell-reinforced encased stone column-supported embankment considering the actual 3D nature of geocells using the finite element program ABAQUS. Parametric studies were carried out to study the stress transfer mechanism, vertical deformation of the foundation soil, and stress-strain variation inside the geocell pockets. It is found from the analyses that with the provision of a geocell layer on top of Geosynthetic Encased Stone Columns (GESC), the stress concentration ratio improved by 47% at the end of consolidation compared to GESC alone. Also, an 80% reduction in foundation surface settlement is observed with geocell-sand mattresses. The geocell-sand mattress decreased the bulging of the stone columns, and almost 80% of the stone column bulging occurred by the end of the embankment construction. The proposed model’s numerical results show that the equivalent composite approach overestimated the stress concentration ratio and bearing capacity. The tensile stresses are non-uniformly distributed in the geocell pockets, and the maximum tensile force was mobilised at the geocell mid-height. Among the various geocell infill materials analysed, the aggregates were best suited considering the stress concentration ratio and vertical settlement. The numerical results supported the idea that encased stone columns with geocells at the embankment base can perform similarly to a geosynthetic reinforced piled embankment system, which is costlier but very efficient. When the modular ratio is more than 40, geocell-reinforced encased stone column-supported embankment is similar to GRPES. © 2022 Informa UK Limited, trading as Taylor & Francis Group.