Faculty Publications
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Item Assessment of ferrous slag with relevance to physico-chemical properties(Springer, 2020) Anjali, M.S.; Poorani, M.; Shrihari, S.; Sunil, B.M.Blast furnace slag is generated as a by-product in the production of iron. Large quantities of slag are visible in the industrial premises that can have adverse effects on the environment. To mitigate such problems, proper environmental management of slag is of great concern. In this regard, a qualitative and quantitative evaluation of ferrous slags such as crystallinity, surface morphology, and elemental composition were done using X-Ray Diffraction and Field Emission Scanning Electron Microscope with EDS (Energy Dispersive X-Ray Spectrometer), respectively. It is also characterized to determine heavy metals and functional groups using Atomic Absorption Spectroscopy and Fourier Transform Infrared Spectroscopy techniques for various geo-environmental applications. The nonplastic slag material showed 85–92% sand-size particles and 8–15% silt-size particles. The SiO2 and CaO values were found to be high followed by Al2O3, MgO, and other compounds. Since slag performed similarly to sand, it could be used as an alternative source of sand. © Springer Nature Singapore Pte Ltd. 2020.Item Effect of wastewaters on the geo-technical properties of laterite(2005) Sunil, B.M.; Shrihari, S.Soil contamination arises from variety of sources, which include acid rain, hazardous liquid and solid waste from industries, animal waste, salt-water intrusion, etc. Literature relevant to the soil-pollutant interaction reveals that soil properties and behaviour is influenced and altered due to contamination by pollutant. The soil pollutant interaction depends on various factors such as nature and chemical composition of soil, dielectric constant of pore fluid, organic matter etc. Sulphur dioxide and oxides of nitrogen are the two most important parameters responsible for acid rain. Atmospheric pollution has resulted in the precipitation having pH less than 5.6 disturbing the nature's delicate balance and also contamination of soil. The soil and ground water contamination will result in Socio-economic and environmental impact. Several studies by various researchers have highlighted the influence of physico-chemical factors on the engineering properties of soil. The alteration of characteristic properties of the soil in the vicinity of industrial plants occurs mainly as a result of their pollution. Literature review on the effect of acid rain on soils indicated that the pH value of soils generally decreased with continuous infiltration. The major soil chemical parameters affecting the contaminant partitioning are hydrogen ion concentration in the soil, which influences all chemical reactions and biological activities. Laterites and lateritic soil have a very important place in Civil Engineering activities in India, especially in the South and Central parts. They form a good foundation material and are composed essentially of hydrated aluminium and iron oxides. In this paper, the results of an investigation on the effect of pH on the characteristic properties of laterite soil procured from the quarry near Mangalore, located on the western coast of south India, has been discussed. The effect of pH on the characteristic properties of laterite was studied under different pH conditions (i.e. pH =5.0, pH=7.0, pH=8.0). The pH of water in which the laterite blocks were soaked (up to ninety days) was maintained using buffers. The important properties considered for the study are: compressive strength of laterite blocks, Atterbeig limits, shear strength properties and chemical characteristics of laterite soil (pH, conductivity, alkalinity, hardness, chloride, sulphate and ammonia nitrogen). From the investigation it is observed that the engineering properties and chemical characteristics of laterite soil are altered in all the three pH conditions (pH=5.0, pH=7.0, pH=8.0). The compressive strength of laterite blocks reduced under all the pH conditio is and considerable reduction in strength was observed when the pH of water was maintained as 5.0. The pH of adjoining water body has remarkable influence on the pH of soil. Accordingly when the pH of water was low (p -1=5.0), the corresponding pH of soil decreased from its initial value. Similarly soil pH increased when the pH of water was maintained as 8.0 for soaking up to ninety days. The various other effects on the engineering behaxiour and chemical characteristics of laterite are noted and discussed in the present work.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 Review on performance of geosynthetic liners in municipal solid waste landfills(Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, 2015) Sunil, B.M.Considerable development has taken place in the area of geosynthetics and their applications since their first use in 1980s in the construction of safe containment of hazardous wastes. Geosynthetic clay liner (GCL) and High density polyethylene (HDPE) geomembrane (GM) liners are widely used in municipal solid waste landfills as a barrier system on the base of the landfill. Satisfactory performance of geosynthetic materials when buried under soil depends on several factors. Geosyntetic liners are subjected to degradation by variation in temperatures or settling of landfills or they will be disintegrated by leachate. Several studies on monitored landfills have shown that geosynthetic liners in municipal solid waste landfills have performed extremely well at controlling leakage in field applications for a couple of decades. However, there have also been some problems reported on the very long term performance these materials. To ensure that long-term contamination does not occur, it is important that the durability of GCL and GM is maintained over the contaminating lifespan of the landfill. Some of the factors that influence very long term performance of GCL/GM/composite liners are particle size, strength and initial water content of subgrade soil, desiccation, the effect of daily thermal cycles etc. This paper examines some of these factors and the mechanisms of performance of geosynthetic liners were reviewed in order to supply reference to the study in this field.Item The Need for Unsaturated Soil Mechanics: A Brief Review(Springer Science and Business Media Deutschland GmbH, 2021) Ujwala Shenoy, K.; Babu Narayan, K.S.B.; Sunil, B.M.Soils exhibit seasonal saturation and desiccation, often resulting in varying degrees of moisture content. In practice, soil is seldom fully saturated. When it is completely dry or wet, it behaves as a two-phase system. Otherwise, the moisture content within the interstices of soil vary, leading to partially saturated conditions. Unsaturated soil condition has significant influence on soil behaviour. This paper presents a brief review of the emergence of unsaturated soil mechanics and its applications. © 2021, Springer Nature Singapore Pte Ltd.Item Swell-Compressibility Behavior of Geopolymer Blended Expansive Clays(Springer Science and Business Media Deutschland GmbH, 2021) Thotakura, V.; Sunil, B.M.; Chaudhary, B.This paper presents the influence of GGBS-based geopolymer on swell-compressibility characteristics of oven-dry, expansive clay passing 4.75 mm sieve. One-dimensional swell-consolidation tests were conducted on the expansive clay passing through 4.75 mm sieve to which GGBS was added at 0, 5, 10, 15, and 20% by dry weight of the clay. Rate of heave, swell potential, swelling pressure, and linear shrinkage were evaluated. Rate of heave and swell potential decreased significantly with increase in GGBS content. The paper also explores the microstructure behavior and surface texture of the GGBS-based geopolymer–clay blends using the scanning electron microscopy (SEM). The SEM results revealed that the higher Si/Al compounds increase the dense phase of geopolymer products. Moreover, geopolymer synthesis can contribute to the bulk utilization of industrial by-products. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Assessment of Seismic Liquefaction of Soils Using Swarm-Assisted Optimization Algorithm(Springer Science and Business Media Deutschland GmbH, 2021) Thotakura, V.; Durga Prasad, C.D.; Chaudhary, B.; Sunil, B.M.Assessment of liquefaction potential of soils due to the earthquake has been carried out in this research using the nature-inspired Metaheuristic swarm-assisted algorithm (PSO). An assessment has been made on the basis of actual field data from the previous research. The field data consists of 59 sets having variables of total stress of soil (⌠o), effective stress of the soil (⌠′o), percentage fines, mean size of soil particles (D50), standard penetration value (SPT), the equivalent dynamic shear stress (Tav/⌠′o), maximum horizontal acceleration at ground surface (a/g) and the earthquake magnitude (M). PSO-based models were developed for both single variable and multivariable linear approaches. The results revealed that for the assessment of liquefaction of soils, the developed PSO models perform good estimations in terms of the errors and convergent solution. And also, with a damping coefficient and varying input variables, there is a significant improvement in the best solution. These developed models can be useful for practicing engineers in the field. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item A Study on Aquaculture Waste Leachate Transport Through Soil(Springer Science and Business Media Deutschland GmbH, 2023) Thotakura, T.V.; Sunil, B.M.; Chaudhary, B.Aquaculture waste is one of the emerging wastes due to rapid expansion and intensification of aquaculture practices and less attention has been paid for environmental concern as compared with municipal waste. Moreover, in the delta region of Andhra Pradesh, nearly one-third of the land cover is occupied by the aquaculture ponds. Major contaminants in aquaculture ponds are rich in nutrients, chemicals, disinfectants, feed residues, metals, minerals, and nitrates. This paper presents the aquaculture waste leachate and clay interaction. Our findings revealed that ammonia interaction with the clay particles significantly influence the hydraulic behavior of the clays. Further, long-term clay-leachate interactions lead to negative environmental consequences. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Utilization of GGBS-Based Geopolymer Lateritic Soils for Sustainable Pavements(Springer Science and Business Media Deutschland GmbH, 2023) Thotakura, T.V.; Sunil, B.M.; Venkata Rao, M.V.Nowadays geopolymers have been recognized as eco-friendly materials as well as potential replacement of ordinary Portland cement (OPC) and lime, which are cementitious materials with three-dimensional tetrahedral frameworks of Al and Si. This paper presents experimental investigation on compaction characteristics such as optimum moisture content (OMC) and maximum dry density (MDD) and unconfined compressive strength (UCS) of a lateritic soil chemically altered with alkali activator along with precursor as ground granulated blast furnace slag (GGBS) with varying amounts of GGBS content. GGBS was added to the lateritic soil up to 30% in increments of 5%. Scanning electron microscopy (SEM) was undertaken on the geopolymer blends to know the micro-structural behaviour and chemical compounds. The results revealed that the unconfined compressive strength (UCS) of the GGBS-based geopolymer soils improved with addition of GGBS content. The micro-structural analysis confirmed the both pozzolanic reaction and ionic exchange takes place in the alkali-activated lateritic blends. The impetus for the utilization of geopolymers can be consuming GGBS in large quantities in their synthesis with the potential to reduce the use of high carbon footprint ordinary Portland cement. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Understanding the Role of Biological Oxygen Demand in Aquaculture Waters in the Western Delta Region of Andhra Pradesh(Springer Science and Business Media Deutschland GmbH, 2023) Thotakura, T.V.; Sunil, B.M.; Chaudhary, B.The aquaculture industry with intensive farming activities has been gaining potential benefits to the nation’s economic growth and food security. However, due to intensive farming, harmful pollutants are emerging with a higher concentration of biological oxygen demand (BOD), chemical oxygen demand (COD), and ammonia nitrates are more concerns. This study presents the role and assessment of BOD for the aquaculture ponds in the western delta region of Andhra Pradesh. The collected water samples at various locations in the study area have been tested for physicochemical characteristics and the test data used for BOD prediction. For evaluating the sensitivity of the prediction model, particle swarm optimization (PSO) with variations of inertia weight and damping factors is used to obtain the best global solution. As a result, prediction models developed for assessing BOD using PSO show convergent predictions. So, based on the prediction results, the implementation of prediction models of BOD using PSO could be helpful for sustainable aquaculture management in the western delta region of Andhra Pradesh. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.