Faculty Publications
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Item Numerical Study on Bearing Capacity Estimation of Circular Footing on Sand Reinforced with Sisal Geotextile(Springer Science and Business Media Deutschland GmbH, 2025) Jena, S.; Khatri, V.N.; Nainegali, L.This paper presents a study on estimating the bearing capacity of shallow circular footings on sand. In this regard, finite element analysis is conducted, assuming that the sand follows Bolton’s model with a relative density of 75%. Initially, the bearing capacity is determined for unreinforced sand conditions, followed by the placement of geotextile at different depths. The results indicate a significant increase in the ultimate bearing capacity of the footing, up to 2.68 times, compared to the unreinforced case, precisely when the geotextile is placed at a depth of 0.25 times the footing diameter. These findings suggest that sisal geotextile can effectively serve as a reinforcement material for addressing various temporary foundation-related problems. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.Item Effects of Uncertain Parameters on the Performance of Single Batter Piles Embedded in Laterally Spreading Ground(Springer Science and Business Media Deutschland GmbH, 2025) Kumar, S.; Sarkar, R.; Nainegali, L.The seismic performance of batter piles is still the least investigated in comparison to vertical piles, though batter piles may offer a prospective solution in case of laterally spreading ground. In this study, a comprehensive investigation is presented for the performance of a single batter pile (both positive and negative) in comparison to the vertical pile considering spreading ground movement. Beam on Nonlinear Winkler foundation (BNWF) approach is considered for modelling the soil-pile systems, and models are developed in the open-source programmer OpenSees. The study considers a three-layer soil profile with a liquefiable layer sandwiched between a non-liquefiable surface crust and the base layer. The following five critical parameters were considered to be uncertain in considering the effects of uncertainty on performance: batter angles, thickness of liquefiable layer, ground slope, relative density of liquefiable layer, and slenderness ratio. An exhaustive probabilistic investigation through response surface methodology was carried out to evaluate the effects of different uncertain parameters on the performance of the pile foundations. The study indicated that the performance of negative batter piles is superior to the vertical and positive batter piles. Further, prediction equations for maximum pile head displacement and bending moment have been developed for piles with different batter angles. The study is supposed to be helpful for practising design engineers to adopt batter piles in seismic conditions. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.Item Static and dynamic performance of single batter piles embedded in slope(Springer, 2024) Kumar, S.; Najar, D.S.; Sarkar, R.; Nainegali, L.The performance of pile foundations embedded in the sloping ground has received the least attention. Further, considering piles with batter angles, the investigation is even more limited. In this study, 3D non-linear finite element analyses were conducted to investigate the lateral load-carrying behaviour of vertical and batter (with angles -5°, +5°, -10° and +10°) pile foundations embedded in slope. Firstly, static analyses were performed, and the behaviour of the batter piles was compared with the vertical piles, considering the piles are embedded in a 30° slope of height 5.0 m with medium-stiff clay. It was observed that the capacity of piles reduces when they are installed on sloping ground. Negative batter piles were found to be more effective than the vertical piles in the slope. Next, the performances of the piles were investigated for dynamic lateral loading. It was inferred that the negative batter piles provide better resistance under lateral loading than the vertical and positive batter piles in sloping ground under dynamic loading as well. © Indian Academy of Sciences 2024.Item Study on Physical, Mechanical, Morphological, and Crystallographic Properties of Chemically Treated Sisal Fibers(Korean Fiber Society, 2024) Jena, S.; Khatri, V.N.; Nainegali, L.; Dutta, R.K.This research is focused on the physical, mechanical, morphological, elemental, and crystallographic properties of untreated, chemically treated, and emulsion-coated sisal fibers. Physical properties, such as diameter and water absorption, were investigated, while mechanical properties, including tensile strength, elongation at break, and modulus of elasticity, were assessed. The findings indicate a significant enhancement in tensile strength (up to 96.7%) and elastic modulus values (up to 214.43%) after chemical treatment, accompanied by a decrease in elongation at break (up to 56.8%). Interestingly, emulsion coating reduced the tensile strength and elastic modulus values, with a marginal increase in elongation at break for treated fibers. The fibers subjected to benzoylation exhibited the highest tensile strength and elastic modulus, followed by alkali-treated fibers. This trend was consistent for emulsion-coated fibers as well. The study outcomes were substantiated by examining the morphological, elemental, and crystallographic aspects of untreated and treated/coated fibers, indicating their suitability for diverse engineering applications. © The Author(s), under exclusive licence to the Korean Fiber Society 2024.Item Slope stabilization of coal mine overburden dumps: life cycle environmental sustainability assessment of alternatives(Springer Science and Business Media Deutschland GmbH, 2024) Kumar, A.; Nainegali, L.; Das, S.K.; Reddy, K.R.; Mishra, A.The stability of coalmine overburden dumps is a crucial aspect and often requires a slope stabilization method in place to prevent slope failures. Mechanical methods like benching, gabion wall construction, geogrid reinforcement, and biological methods like the use of vegetation can suffice the need for slope stabilization. In this study, a life cycle assessment of the above-mentioned methods was performed to obtain the environmental impacts through various midpoint impact categories considering a “cradle-to-site” assessment. The system boundary for each method was created using the involved activities and associated equipment and energy needs. The Ecoinvent 3.0 database and TRACI assessment method were used to perform the life cycle impact assessment using SimaPro software. The results show that the use of vegetation caused the least impact. The highest impact under the majority midpoint categories was caused by geogrid reinforcement followed by benching, which was mostly attributed to the geogrid production and OB handling activities, respectively. The carcinogenic, followed by ecotoxicity and fossil fuel depletions, were the most impacted categories for the mechanical methods, which may be due to the release of chemical pollutants during material production or handling. Adherence to the overburden dump management guidelines and the use of renewable sources of energy are the two major aspects that can drastically curb the emission load on the environment, thus inching towards the goal of sustainability while adopting slope stabilization measures for overburden dumps. Besides imparting stability, plants provide a diverse solution to the other ills associated with the overburden storage and management. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.Item Bearing ratio behaviour of sisal geotextile reinforced fly ash overlying clay(Taylor and Francis Ltd., 2025) Jena, S.; Khatri, V.N.; Nainegali, L.The paper examines the bearing ratio behaviour of sisal geotextile reinforced fly ash over clay. It also evaluates the effects of alkali treatment and emulsion coating of the geotextile on the bearing ratio at optimal placement depths. Results show that using one, two, and three layers of untreated geotextile increased the CBR by 19.6%, 55%, and 78% at different placement depths (1.5B, 1B, and 0.5B), where B is the plunger diameter. Alkali-treated and emulsion-coated geotextiles increased the CBR by 24.6% and 15.6%, respectively. However, soaking reduced the CBR by 76.6%, with the greatest decrease observed in triple-reinforced alkali-treated samples. Punching tests and morphological analyses supported the study outcomes. A numerical study of a pavement section, based on the experimental results, recommends sisal geotextile for rural roads using load equivalency factors and the structural number approach. © 2025 Informa UK Limited, trading as Taylor & Francis Group.Item Effects of uncertainty of critical parameters on performance of piles with different batter angles in laterally spreading ground: development of prediction models(Taylor and Francis Ltd., 2025) Kumar, S.; Sarkar, R.; Nainegali, L.Failures of vertical piles are common under earthquake loading, especially in laterally spreading ground conditions. Performance is supposed to be better for batter piles due to their higher lateral load-carrying capacity. However, the framework of the design of batter piles is still not available for laterally spreading ground for different degrees of batter, considering the associated uncertainties. This paper investigates the effects of uncertainties on the performance of batter piles in laterally spreading ground. The beam on nonlinear Winkler foundation (BNWF) approach was considered for modelling the soil-pile systems. Nonlinear analyses were carried out for cosine-shaped ground deformation profiles. Effects of the uncertainty of critical parameters such as ground slope, relative density and thickness of the liquefying layer, batter angle, and slenderness ratio of the piles were investigated through a factorial design approach. A central composite design approach was adopted to investigate the curvature effects of the uncertain parameters. It was observed that the negative batter piles perform significantly better than their counterparts of vertical and positive batter piles. This study proposes prediction models for maximum bending moment and pile head displacement for piles with different batter angles, considering a three-layered laterally spreading ground. © 2025 Informa UK Limited, trading as Taylor & Francis Group.Item A Three-Dimensional Investigation on the Efficacy of Different Configuration Settings of Micropiles in Enhancement of Seismic Slope Stability(Springer Science and Business Media Deutschland GmbH, 2025) Kumar, S.; Anand, A.; Sarkar, R.; Nainegali, L.Micropiles have emerged as an effective measure to strengthen the stability of slopes. However, its efficacy in improving the stability of slopes under seismic loading conditions has not been fully established. This paper intends to investigate the performance of micropiles with different configurations to improve the stability of a slope under static and seismic loading conditions. A clayey slope of height 10 m underlain by a sandy soil layer was adopted for the investigation. Three-dimensional nonlinear finite element models were developed for the slope-micropile systems. Five different configurations of micropiles, considering a single micropile on two faces of the slope, were adopted for investigation. Further, a study was carried out with eight different combinations of these configurations of micropiles for strengthening the slope. Initially, static analyses were carried out for the different configurations of micropiles. Next, for seismic loading, pseudo-static analyses were carried out for all the configurations. The efficacy of different configurations of micropiles was compared through the factor of safety obtained. Analyses were also carried out considering the water table, and the efficacy of micropiles was established in the same way. Finally, nonlinear dynamic analyses were carried out for different configurations of micropiles with real earthquake time history, and the improvement in seismic performance of the micropile-strengthened slope was reported. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.Item Root reinforcement of herbaceous vegetation for stabilization of coal mine overburden dump slopes(Springer Science and Business Media Deutschland GmbH, 2025) Kumar, A.; Nainegali, L.; Das, S.K.; Reddy, K.R.Slope instability of coal mine overburden dumps poses significant challenges to mining safety and environmental sustainability. This study investigates the potential for root reinforcement offered by herbaceous vegetation (Dendrocalamus strictus and Cymbopogon citratus) for enhanced slope stability. A series of pot experiments were conducted to grow grasses with the coal mine overburden material. The survival and growth of grasses in the nutrient-devoid overburden are critical because they directly impact the effectiveness of root reinforcement. Therefore, the effect of amendment quantity on plant growth was assessed. A direct shear box test was conducted on the bare and rooted samples using a fabricated internal shear test assembly to determine the strength. The higher peak shear stress and dilatancy angle observed for the rooted specimens were due to the high root tensile strength mobilizing the shear stresses. The results of shear tests were subsequently employed in limit equilibrium slope stability analyses where material heterogeneity was considered to account for uncertainties linked to material properties. The deterministic analysis provided insights into the expected improvements in slope stability due to root reinforcement, offering a baseline for comparison. Meanwhile, the probabilistic analysis considered the variability in material properties, thus providing a more comprehensive understanding of the uncertainty associated with the slope stability assessment regarding the reliability index and probability of failure. By combining experimental investigations with rigorous analytical approaches, this study enhances our understanding of how grassroots reinforcement can enhance the stability of coal mine overburden dumps. © The Author(s), under exclusive license to Springer-Verlag GmbH Germany, part of Springer Nature 2025.