Journal Articles
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Item Effect of pH on the geotechnical properties of laterite(2006) Sunil, B.M.; Nayak, S.; Shrihari, S.Environmental Geotechnology has emerged as an interdisciplinary science, aiming and forecasting, analyzing and solving the geotechnical problems involving the influence of environmental factors. Lateritic soil of west coast region of India was studied to investigate the effect of soaking on the engineering properties and chemical characteristics of soil, soaked in different pH solutions (pH = 5.0, pH = 7.0, pH = 8.0). 12 N hydrochloric acid and 15 M ammonia solution were used to monitor the pH of the solution for about ninety days. Results showed that the pH of the solution has strong influence on the chemical characteristics of lateritic soil. The engineering properties of soil are altered when compared with the initial characteristics of the soil. The reason for this observed behavior of the soil is addressed in this paper. © 2006 Elsevier B.V. All rights reserved.Item Hydraulic and compaction characteristics of leachate-contaminated lateritic soil(2007) Nayak, S.; Sunil, B.M.; Shrihari, S.Large quantities of leachate-contaminated lateritic soil results from dump yards in the southwest coast of India. These dump yards receive large quantities of municipal solid waste which includes chemical, industrial and biomedical wastes. Large areas of land are currently being used for this purpose. An extensive laboratory testing program was carried out to determine the compaction characteristics and hydraulic conductivity of clean and contaminated lateritic soil. Batch tests were used to study the immediate effect of leachate contamination on the properties of lateritic soil. Contaminated specimens were prepared by mixing the lateritic soil with leachate in the amount of 5%, 10% and 20% by weight to vary the degree of contamination. The results indicated a small reduction in maximum dry density and an increase in hydraulic conductivity due to leachate-contamination. The change induced by chemical reaction in the microstructure of the soil was studied by scanning electron microscope before and after contamination of soil with leachate. The structure of the leachate contaminated soil sample appeared to be aggregated in scanning electron microscope analysis. The aggregated structure increases the effective pore space and thus increases the hydraulic conductivity. Fifty percent increase in hydraulic conductivity was observed for specimens prepared at standard Proctor density and mixed with 20% leachate. Compaction characteristics did not change much with the presence of leachate up to 10%. With 20% leachate the maximum dry density decreased slightly indicating excess leachate in the soil. However the changes are not significant. © 2007 Elsevier B.V. All rights reserved.Item Shear strength characteristics and chemical characteristics of leachate-contaminated lateritic soil(2009) Sunil, B.M.; Shrihari, S.; Nayak, S.Leachate is a hazardous liquid and is a major cause of concern in landfills. Numerous environmental problems such as soil and groundwater contamination occur in unlined landfills due to free flow of leachate. Large quantities of leachate-contaminated soils result from open dumping in the study area. These dump yards receive large quantities of municipal solid waste which includes chemical and industrial wastes. Large areas of land are currently being used for this purpose. An extensive laboratory testing program was carried out to determine the properties of clean and contaminated lateritic soils. Laboratory prepared municipal solid waste leachate was used in this study. Contaminated specimens were prepared by mixing the soils with MSW leachate in the increments of 0%, 5%, 10% and 20% by weight to vary the degree of contamination. The results showed that the MSW leachate affects the Atterberg limits, shear strength and chemical characteristics of the lateritic soils. The liquid limit and the plasticity index of the lateritic soils increases with MSW leachate concentration. For specimens tested at the Proctor density, effective cohesion increases and effective friction angle decreases due to increase in leachate concentration. This is attributed due to the increase in clay content of lateritic soil after interaction with the leachate. This led to increase in cohesion parameter and the friction angle decreases. The pH measurements of lateritic soil contaminated with MSW leachate indicated an increase in pH values. This is also accompanied by slight increase in the cation exchange capacity of the soil. The change in chemical characteristics of lateritic soil contributed due to addition of leachate may be detrimental to foundation concrete in real field conditions. The present work deals with an attempt to study the effect of leachate on the Atterberg limits, shear strength properties and chemical characteristics of lateritic soil. © 2009 Elsevier B.V. All rights reserved.Item Interactions Between Soils and Laboratory Simulated Electrolyte Solution(2010) Nayak, S.; Sunil, B.M.; Shrihari, S.; Sivapullaiah, P.V.To study the impact of salt water intrusion on two types of soils from west coast region of India were investigated in the laboratory. The key characteristics evaluated included Atterberg limits, compaction characteristics, hydraulic conductivity and chemical characteristics of selected soils. The sea at this coast receives effluent from different points and hence the characteristics change with time and locality. Therefore, to maintain uniform composition, 0.5 N sodium chloride solution (NaCl) was prepared in the laboratory and batch tests were used to determine the immediate effect on soils. Soil specimens were prepared by mixing the soils with 0.5 N NaCl in the increments of 0, 5, 10 and 20% by weight to vary the degree of contamination. Experimental results of soils mixed with 0.5 N NaCl showed that the maximum dry density increases and the optimum moisture content (OMC) decreases with increasing sodium chloride concentration. The study also revealed that the hydraulic conductivity of the soils tested increases with increase in sodium chloride concentration. The Atterberg limits of contaminated specimens show a remarkable change when compared with uncontaminated specimens. © 2010 Springer Science+Business Media B.V.Item 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.Item Effect of Drying on the Index Properties of Lateritic Soils(2012) Sunil, B.M.; Krishnappa, H.Due to significant variation in geological and climatic conditions the characteristics of lateritic soils vary from place to place. Because of the prevailing climatic conditions, the laterites and lateritic soils of a particular region may be different from those found in other parts of the world. Some investigators report that the pretest drying has significant effect on the properties of soils. In such studies the authors associate the effect of drying on the properties of soils due to the mineralogy of soil. From this context there is a need to investigate the effect of sample preparation on lateritic soils prior to testing. In the present study lateritic soils from different sources in west coast region of India were studied to investigate the effect of drying on their index properties. Due to pretest drying it is observed from the results that there is a significant change in Atterberg limits and other properties of soils tested. These changes are attributed due to aggregation of particles. The observed changes are found to be permanent. © 2012 Springer Science+Business Media B.V.Item Influence of Drying Temperature on Three Soils Physical Properties(Springer International Publishing, 2016) Sunil, B.M.; Deepa, A.V.Changes in plasticity characteristics of three soils upon drying are examined in this paper. These changes are attributed to aggregation of particles. The key characteristic evaluated was the impact of drying temperature on the index properties, compaction characteristics and California bearing ratio. The study found the effect of drying strongly depended on soil type, mineralogy or presence of cementing agents. The observed changes are found to be permanent and the implications are that these changes may affect the field performance of test soils. © 2016, Springer International Publishing Switzerland.Item Durability studies on concrete with partial replacement of cement and fine aggregates by fly ash and tailing material(Techno Press technop2@chollian.net, 2017) Sunil, B.M.; Manjunatha, L.S.; Yaragal, S.C.Commonly used concrete in general, consists of cement, fine aggregate, coarse aggregate and water. Natural river sand is the most commonly used material as fine aggregate in concrete. One of the important requirements of concrete is that it should be durable under certain conditions of exposure. The durability of concrete is defined as its ability to resist weathering action, chemical attack or any other process of deterioration. Durable concrete will retain its original form, quality and serviceability when exposed to its environment. Deterioration can occur in various forms such as alkali aggregate expansion, freeze-thaw expansion, salt scaling by de-icing salts, shrinkage, attack on the reinforcement due to carbonation, sulphate attack on exposure to ground water, sea water attack and corrosion caused by salts. Addition of admixtures may control these effects. In this paper, an attempt has been made to replace part of fine aggregate by tailing material and part of cement by fly ash to improve the durability of concrete. The various durability tests performed were chemical attack tests such as sulphate attack, chloride attack and acid attack test and water absorption test. The concrete blend with 35% Tailing Material (TM) in place of river sand and 20% Fly Ash (FA) in place of OPC, has exhibited higher durability characteristics. © 2017 Techno-Press, Ltd.Item Experimental studies of slag filter for drinking water treatment(Elsevier B.V., 2019) Anjali, M.S.; Shrihari, S.; Sunil, B.M.The study examined the use of granulated blast furnace slag, an industrial by-product from ferrous industries for drinking water treatment. A laboratory scale filter, 9 cm diameter and 40 cm with iron slag media supported on a gravel bed could completely remove turbidity, total suspended solids and colour for an average influent loading of 28.26 NTU, 128.85 mg/L and 177.05 PCU respectively at a filtration rate of 0.32 m3hr?1m?2. The average removal of hardness, sulphate, nitrate, chloride and iron were 35%, 83%, 71%, 28% and 94% for an average influent loading of 579.79 mgL?1, 367.72 mgL?1, 120.52 mgL?1, 355.67 mgL?1 and 1.49 mgL?1respectively. Doubling the filtration rate with slight increase in loading rate showed 100% removal for turbidity, suspended solids and colour whereas hardness, sulphate, nitrate, chloride and iron removals were 27%, 73%, 86%, 28% and 95% respectively. The maximum head loss for continuous operation without backwash was only 75 mm. Intermittent washing helped to improve the filtered water quality for various filtration and loading rates. An increase in the rate of filtration up to 1.28 m3hr?1m?2 did not have any impact on the quality of treated water except sulphate and nitrate. After backwashing, there was considerable improvement in chloride removal. The removal of physicochemical parameters was due to precipitation, adsorption and ion exchange with the formation of products both at the surface and within the slag media. FTIR and XRD results also confirmed the behaviour of slag as an anion exchange resin. The maximum head loss observed in slag filter was 190 mm at the highest loading level and filtration rate. © 2019 Elsevier B.V.Item Effect of ammonia on the hydraulic conductivity and adsorption characteristics of lithomargic clay - Bentonite barrier in landfills(Elsevier Ltd, 2022) Aswathy, C.M.; Sunil, B.M.Alteration of characteristic properties of the liner material occurs mainly due to interaction with contaminants present in the landfill leachate. The present study deals with the effect of inorganic contaminants on the behaviour of bentonite-based landfill liner material. Saturated hydraulic conductivity, unconfined compressive strength and compaction characteristics of the lithomargic clay and its blends permeated with an inorganic contaminant (ammonia) were evaluated. Experiments were conducted by blending lithomargic clay with 5%, 7.5% and 10% bentonite. The results showed that hydraulic conductivity decreased from an initial value of 3 × 10-8 m/s to 6.83 × 10-11 m/s. Unconfined compressive strength at wet of optimum and maximum dry density of blended lithomargic clay also reduced slightly. Adsorption studies were conducted, and the coefficient of distribution (Kd) for blended lithomargic clay with 5% and 10% was found to be 60.46 L/kg and 94.74 L/kg, respectively. The Kd values indicate good adsorption characteristics of bentonite-based material. Overall, the results showed that lithomargic clay blended with bentonite is a suitable alternative barrier for constructing engineered landfills to prevent environmental degradation and other health effects. © 2022 Elsevier Ltd.