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Author: search.filters.author.Nayak, S.Subject: search.filters.subject.Lithomargic clays

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    Microfabric and mineralogical studies using sem and xrd on the lithomargic clay stabilized with cement and quarry dust
    (CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2011) Sarvade, P.G.; Nayak, S.
    The infrastructural development activities due to rapid urbanization, low lying agricultural and marshy lands in and around Mangalore (India) are being converted into estates with locally available lithomargic clay. These filled up areas pose problems of low bearing capacity as well as excessive settlements. As long as this soil is confined and dry, there is a very little or no problem, when it comes in contact with water, it loses its strength. The engineering properties of this soil are enhanced by the addition of additives (cement, quarry dust and quarry dust +cement). In the present study the microfabric and mineralogical aspects of the stabilized lithomargic clay is studied using Scanning Electron Microscope (SEM) and X-ray diffractometer (XRD). The XRD analysis of lithomargic clay stabilized with cement, revealed the formation ettringite, CSH and CAH. The SEM analysis revealed change in the soil structure due to the addition of cement and quarry dust. © 2011 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Geotechnical characteristics of lithomargic clay blended with marine clay as landfill liner material
    (CAFET INNOVA Technical Society cafetinnova@gmail.com 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2012) Allamaprabhu, K.; Sunil, B.M.; Nayak, S.; Fernandes, S.; Zafar, M.
    This paper reports a series of laboratory tests conducted on lithomargic clay (shedi soil), which is widespread over part of southwest coast of India, to assess whether it could be used as compacted clay liner for hydraulic barriers in engineered landfill. In order to assess the suitability of lithomarge as a barrier material, following tests such as index properties, compaction characteristics, hydraulic conductivity and unconfined compressive strength of the soil were conducted in the laboratory. From the studies, it is found that lithomargic soil is near to the recommended specifications for soils to be used as liner material. Suitable materials for soil liners are then obtained by blending different types of locally available soils to achieve the required low hydraulic conductivity and good strength. To achieve specifications for the liner material lithomargic clay is blended with 15% and 20% marine clay by weight of lithomargic clay. From standard compaction control, the blended soil shows hydraulic conductivity lower than the 1x10-7 cm/s. Acceptable zones (AZ) are constructed on the compaction plane to meet design objectives for hydraulic conductivity. It's strength properties show that the soil possesses higher strength than the recommended minimum strength of 200kPa, to support the overburden pressure imposed by the waste body. From the laboratory test results, it can be concluded that lithomargic clay blended with marine clay satisfies the requirements for a good soil liner material. © 2012 CAFET-INNOVA TECHNICAL SOCIETY.
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    Performance of granular columns in dispersive soils
    (Thomas Telford Services Ltd ttjournals@ice.org.uk, 2014) Nayak, S.; Dheerendra Babu, M.R.; Shivashankar, R.; James, N.
    The soils found abundantly along the Konkan belt in peninsular India are lateritic soils and lithomargic clays. The locally available lithomargic clayey soils are problematic in the sense that their strength reduces drastically under saturation conditions, which is typical behaviour of the dispersive type of soil. Most foundations are placed on this soil layer. This paper presents results from a series of laboratory plate load tests carried out in unit cell tanks to investigate the behavior of granular columns in these weak (lithomargic clay) grounds. Tests are carried out with two types of loading: with the entire area in the unit cell tank loaded, to estimate the stiffness of the improved ground; and with only the granular column area loaded, to estimate its limiting axial capacity. Investigations were carried out by varying the area ratio (or spacing), diameter of granular columns, end condition and column configuration. The load-settlement behaviour, stiffness and bulging behaviour of granular columns are analyzed. It is found that the ground treated with granular columns exhibits a high load-carrying capacity and stiffness, and a significant reduction in settlement, compared with the untreated ground. © Ice publishing: All rights reserved.
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    Influence of Granulated Blast Furnace Slag and Cement on the Strength Properties of Lithomargic Clay
    (Springer India sanjiv.goswami@springer.co.in, 2017) C. Sekhar, D.C.; Nayak, S.; Preetham, H.K.
    Utilizing industrial byproducts in soil stabilization benefits the economic, environmental and social benefits. Granulated blast furnace slag is a byproduct of iron and steel industry having oxides similar to that of cement but in different proportions. This study describes experimental results achieved by the use of granulated blast furnace slag (GBFS) and cement in stabilizing lithomargic clay for geotechnical applications. Soil was replaced by GBFS in percentages of 10, 15, 20, 25, 30, 35, 40, 45, 50% and cement of 2, 4, 6, and 8% by dry weight of soil is added. Various experimental studies like specific gravity, Atterberg limits, compaction, UCS, CBR and triaxial compression test, were performed on samples to understand the effect of these mixes on their few index and strength properties. The study also includes an investigation on a combination of optimum percentage of GBFS with varying percentage of cement and lime on their shear parameters. The study result shows significant improvement in the strength properties of the mixes. Hence it can be concluded that lithomargic clay stabilized with GBFS and cement/lime satisfy the strength requisite to be employed in the numerous geotechnical applications. © 2017, Indian Geotechnical Society.
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    Utilization of granulated blast furnace slag and cement in the manufacture of compressed stabilized earth blocks
    (Elsevier Ltd, 2018) C. Sekhar, D.; Nayak, S.
    This study involves the investigation on utilization of granulated blast furnace slag (GBFS) and cement in the manufacture of compressed stabilized earth blocks (CSEB). Two locally available soils from Dakshina Kannada district, Karnataka, India were tested for their index and strength properties with replacement of granulated blast furnace slag (GBFS). An optimum percentage of replacement of GBFS was established and then varying percentages of cement was added for the production of compressed stabilized earth blocks (CSEBs). This stabilized soil was used for the manufacture of blocks of size 305 mm × 143 mm × 105 mm. All the blocks were cast to a target density, followed by the curing for 28 days. The blocks were subjected to compression test and water absorption test according to Indian Standard (IS) specifications. The test results showed that the CSEBs prepared with GBFS and cement can be utilized in masonry for load bearing wall construction. A small percentage of cement is sufficient for manufacturing the CSEBs when optimum GBFS content is replaced with that of soil, thereby reducing the energy consumption. © 2018 Elsevier Ltd
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    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.
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    Experimental Investigation and Performance Evaluation of Lithomargic Clay Stabilized with Granulated Blast Furnace Slag and Calcium Chloride
    (Springer Science and Business Media Deutschland GmbH, 2022) Lakkimsetti, B.; Nayak, S.
    South-western coast of India has vast deposits of highly problematic silty soil normally referred to as lithomargic clay in the literature. This problematic silty soil is characterized by its high sensitivity to moisture content with high erosion potential and low shear strength. This paper attempts to address this problem by chemical stabilization of lithomargic clay using Calcium chloride (CaCl2) and an industrial by-product obtained from the iron industry, i.e., granulated blast furnace slag (GBFS). Disposing of huge quantities of GBFS poses a severe impact on the environment. GBFS has high pozzolanic activity, and utilizing it for the stabilization of soils would be a sustainable and eco-friendly solution. To optimize CaCl2 and GBFS contents for achieving better geotechnical properties of the stabilized soil and to understand the mechanism governing the improvement, a series of laboratory experiments were performed on lithomargic clay by stabilizing it with different amounts of CaCl2 and GBFS. Optimum CaCl2 and GBFS contents obtained from the laboratory experiments are 6% and 20%, respectively, and a significant increase in strength was achieved with this optimized mix. Scanning electron microscope and X-ray diffraction analyses were carried out on the powdered samples of the treated soil, and the improvement in strength was justified through the microstructural changes observed due to the formation of cementitious compounds. Response of strip footings lying on unstabilized, and stabilized soils was analyzed using PLAXIS-2D. Numerical simulations showed a significant increase in the allowable bearing pressure with stabilization of lithomargic clay with GBFS and CaCl2. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.