Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
45 results
Search Results
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 New polymeric and inorganic membrane materials for water separation(Elsevier, 2023) Nayak, S.; Isloor, A.M.; Maddodi, B.S.Overuse and exploitation of water resources have caused the global water crisis. To overcome the problem, wastewater reuse has become essential for the survival of humankind. Hence, humans must depend on technologies that efficiently separate contaminants from water and make it reusable for domestic, agricultural, and industrial utilization. To achieve this, membrane technology is the ideal technology, so it has been pursued for the same reason over many decades. It has undergone extensive research and development in its materials processing, fabrication, and applications. In order to achieve a high degree of efficiency in the separation process, there is a need for new membrane materials as conventional materials are not sustainable and efficient enough to separate pollutants like heavy metals, pathogens, dyes, natural organic matter, inorganic salts, and other emerging contaminants from the water. This chapter presents different classifications of membranes and mainly discusses the development of new polymeric and inorganic membrane materials, their performance, application, and the challenges that need to be addressed for their usage in membrane technology-based water separation. © 2024 Elsevier Inc. All rights reserved.Item Soil-leachate interaction and their effects on hydraulic conductivity and compaction characteristics(2008) Sunil, B.M.; Shrihari, S.; Nayak, S.Leachate is the most dangerous component of the solid waste management process. In a small landfill, the amount of leachate generated may not create a serious problem. As the size of landfill and variety of solid wastes disposed increases, large amounts of leachate will be generated and create environmental problems such as leaching of nutrients and heavy metals into the soil which leads to soil and ground water contamination. The problem of change in behaviour of soils on one hand and the contamination of ground water on the other is a cause of concern for geotechnical and environmental engineers. In this paper, results of a laboratory study to determine the effects of leachate contamination on the hydraulic conductivity and compaction characteristics of shedi soil (also known as lithomargic clay) have been presented. The study has indicated that leachate can modify the soil properties and significantly alter the behaviour of soil. There is a general deterioration in soil properties which is attributed to the chemistry of leachate and of soil. The interaction of leachate with soil is responsible for the modified behaviour of the soil.Item Modeling and performance analysis of microturbine based Distributed Generation system, "a review"(2011) Gaonkar, D.N.; Nayak, S.Distributed Generation (DG) is predicted to play an important role in the electric power system in the near future. It is widely accepted that microturbine-generation systems are currently attracting lot of attention to meet users' need in the distributed generation market. In order to gain the benefits of interconnected operation of microturbine generation system (MTG) system with the utility network, their effective modeling and performance analysis are required. This paper presents the recent research efforts in accurate modeling of MTG System and the investigation on various issues related to their interconnected operation and control with the distribution network. © 2011 IEEE.Item Experimental investigation on the stabilization of soft clay using granulated blast furnace slag(Institute of Physics Publishing helen.craven@iop.org, 2019) Preetham, H.K.; Nayak, S.; Surya, E.V.Soft clay is associated with a soft consistency and poor shear strength. High percentage fines lead to higher liquid limit and lower plasticity index. Low bearing capacity and excessive settlement lead to uneconomic engineering structure constructed over it. There is a serious need to mitigate this problem and hence soil stabilization is the need of the hour. In the present study, Granulated Blast Furnace Slag (GBFS) which is an industrial waste/by-product of steel industry is used as a stabilizer to improve the geotechnical property of the soft clay. Soft clay is replaced by granulated blast furnace slag in various percentages by weight (10%, 20%, 30%, 40% and 50%) and examined for its plasticity, compaction and strength properties of the mix. From the experimental investigation, it is shown that the plasticity index decreases and unconfined compressive strength (UCS) increases upon addition of slag to the soil. With the curing age, UCS value increased indicating the chemical reaction between free lime and soil. 40% slag replacing the soft clay is recommended as stabilizer as it gave the maximum increase in UCS value compared to the rest mix. Based on the laboratory work, it can be concluded that granulated blast furnace slag can be used as a potential stabilizer for soft clay and also largely solves the problem of disposal of slag. © 2019 IOP Publishing Ltd. All rights reserved.Item Improvement in the Properties of Red Soil Using Granulated Blast Furnace Slag(Springer Science and Business Media Deutschland GmbH, 2022) Preetham, H.K.; Nayak, S.; Jagapur, P.In the current study, an attempt is made to improve the geotechnical properties of red soil using industrial by-product: Granulated-Blast Furnace Slag (GBFS). Red soil is distributed over large part of the peninsular region in India. Red soil could be effectively stabilized to yield better strength characteristics. GBFS is the primary by-product of the iron and steel industry. Red soil was replaced with varying percentages of admixture (GBFS) by dry weight of soil (5, 10, 15, 20 and 30%). Basic geotechnical properties like specific gravity, Atterberg limits, compaction, unconfined compressive strength (UCS) and triaxial compression test, were performed on the red soil as well as on the mixes as per Indian Standard Codal provisions. From the UCS test results, the optimum percentage of replacement of 15% was found. It was observed that on replacement with admixtures, the liquid limit was found to decrease which reduces the compressibility. The presence of CaO in GBFS has improved the shear strength and shear strength parameters of soil. Thus utilization of granular industrial by-product (GBFS) has proven beneficial in geotechnical structures. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Assessment of the Geotechnical Properties of Red Earth Stabilized Using Quarry Dust and Cement(Springer Science and Business Media Deutschland GmbH, 2022) Nayak, S.; Preetham, H.K.; Prakash, S.D.The present investigation aims at improving the engineering properties of red earth by incorporating quarry dust (QD) and analyze the results thus obtained by conducting a comparative study with the basic soil. Red earth is widely spread over a large part of peninsular India. Red earth/red soil could yield better results by the addition of rough-textured granular quarry dust and a hydraulic binder like cement. QD is the output from the rubble crushing units. Red earth was replaced with different proportions of quarry dust by dry mass of the soil: QD (5–30%, with an increment of 5%) with cement (2–6%) for the optimum QD-soil mix. The geotechnical properties like specific gravity, consistency limits, compaction, unconfined compressive strength (UCS), and triaxial compression test were performed on the red earth as well as on the mixes as per Indian Standard Codal provisions. UCS test results conclude that an optimum percentage of replacement of red earth by QD is 10% which yielded maximum strength than other mixes. It was observed that on replacement of red earth by granular quarry dust and cement, the shear strength properties and other geotechnical properties were improved. Thus, the utilization of granular industrial by-products has proven to be socially and economically beneficial. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item A Review on Methods for Analysis of Laterally Loaded Piles(Springer Science and Business Media Deutschland GmbH, 2022) Babu, A.; Nayak, S.Pile foundations are often subjected to lateral loads and moments due to forces such as wind, waves and earthquake. The lateral response of a single pile is one among the main complex soil-structure interaction problems in foundation engineering. The behavior of the soil-pile system is mainly nonlinear, making the problem more complicated. The lateral load resistance of pile is influenced by the soil pile interaction, which in turn depends on soil properties, pile material, diameter of the pile, pile length, loading type etc. Several methods have been used for the analysis of vertical piles subjected to lateral loads, some of which have gained significant experience in applying the theory to practical situations. Realistic soil-pile interaction and pile behavior under lateral load can be simulated using software based on finite element analyses. A comprehensive literature review of different methods for the analysis of laterally loaded piles is discussed in this paper. The applicability, advantages, limitations and comparison of various methods are also included in the study. For the better understanding the entire review is segregated into different subsections on the basis of nature of analyses. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item An Analysis of Piled Slope with Single Row of Piles Using 2D Finite Element Analysis(Springer Science and Business Media Deutschland GmbH, 2024) Jose, D.; Kolathayar, S.; Nayak, S.The increased frequency of landslides and the associated damages emphasize the need to develop novel techniques for landslide mitigation. Among numerous methods developed till today, an anti-slide pile is an effective tool for controlling slides in landslide-prone areas. The present study assesses the suitability of 2-D FE analysis using the strength reduction method for analyzing a slope stabilized with anti-slide piles. A detailed parametric study was carried out to explore the influence of the position and length of the pile on the factor of safety of pile-reinforced slopes, and the failure mechanism was studied in detail. Fixed head piles improved the safety factor compared to free head piles, and an improvement of 1.5 times was obtained compared with unreinforced slope. Piles located at the crest and toe of the slope were not significantly improving compared to other locations. For fixed head piles, the length of the pile does not affect the factor of safety, and for free head piles, the factor of safety improves with an increase in the length of the pile. For the slope considered in the study, the optimum position of the pile is between the crest and middle portion of the slope, and the optimum length is found to be 20 m for free head piles and 10 m for fixed head piles. The failure mechanism of the piled slope is also explained in detail for each case. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.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.