Faculty Publications
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Item Liquefaction hazard mapping of Chennai, India using SPT data(2011) Anbazhagan, P.; Basavaraj, S.; Premalatha, K.V.Liquefaction hazard is one of the major concerns for earthquake geotechnical engineering. In this paper an attempt has been made to assess liquefaction potential of Chennai city using SPT N values. Chennai is located between 12.75° to 13.25° N and 80.0° to 80.5° E on the southeast coast of India and in the northeast corner of Tamil Nadu. To understand the liquefaction possibility of Chennai city, about 650 Borelogs have been collected from different geotechnical agencies and used for the analysis. These boreholes were drilled for different projects in Chennai, most of them were drilled up to hard stratum and a minimum depth of 10m. SPT borehole data contains information about depth of water table, the classification of soil and the field observed 'N' values, index properties, rock depth. These borehole information are used to prepare N corrected table by applying the universally followed correction factors for liquefaction study. These corrected N values are further used to estimate the factor of safety against liquefaction of soil layer. Based on the factor of safety, the regional liquefaction hazard maps have been developed for depths of 1.5m, 3.0m, 6.0m and 10.0m. To represent the worst scenario, least factor of safety has been identified for each borehole location and mapped. Further the estimated factor of safety against liquefaction is used to estimate liquefaction potential index by considering depth of layer. These results are analyzed and compared in this paper. © 2011 CAFET-INNOVA technical society. All right reserved.Item Physico-mechanical properties of select granitoidal rocks from a part of Pandiyan mobile belt, India(2012) Sivapragasam, C.; Venkat Reddy, D.; Kulandaisamy, K.; Vigneswaran, M.; Senthilkumaran, S.; Sivaprasath, C.; Varun Kumar, M.This study deals with the Physico-mechanical properties of the granites from the Pandiyan mobile belt to identify the suitability of the granite for engineering purposes. The geological characteristics, the mining procedure and mineralogical and engineering properties of the granite samples are estimated through laboratory tests. Based on the results, it is concluded that granitoids of Madurai region is best suited for all the civil engineering works. The granites in Sankarankovil region are more suited as aggregates for road pavements. © 2012 Cafet-Innova Technical Society.Item Land use/land cover changes around Rameshwaram Island, east coast of India(National Institute of Science Communication and Policy Research, 2014) Gowthaman, R.; Dwarakish, G.S.; Sanilkumar, V.Land-use/land cover changes are studied using the Indian Remote Sensing satellite (IRS-1C, IRS-P6) Linear Image Self-scan Sensor (LISS) III data of 1998 and 2010. Coastal land use categories such as sand, vegetation, coral reef and water have been identified using interpretation keys. Results of land-use/land cover assessment based on visual interpretation are presented. The study indicates water body of 178 and 177 km2, sand features of 32 and 32 km2, vegetation of 28 and 35 km2 and coral reef of 5 and 6 km2 respectively. © 2014, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.Item Modeling duration of lateral shifts in mixed traffic conditions(American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2018) Asaithambi, G.; Joseph, J.Traffic on urban roads in developing countries is characterized by wide mix of vehicles with loose lane discipline, which results in parallel movement of vehicles in the same lane. Hence, vehicles not only interact longitudinally with the vehicles ahead but also laterally with vehicles to the sides. Lateral movements have a significant impact on the characteristics of traffic flow and therefore are of great importance in microscopic traffic simulation models. Existing simulation models for mixed traffic conditions model lateral shifts (lateral movements) as an instantaneous process but neglects detailed modeling. However, the duration for lateral shifts is generally in the range of 0.5-15 s. The omission of lateral shift duration from simulation models may have a significant impact on simulation outputs. Also, different vehicle types may have different lateral shift durations due to variations in their physical and operational characteristics. This paper attempts to develop a vehicle-specific lateral shift duration model by considering different explanatory variables such as direction of lateral shift, available space gaps, speeds of subject vehicle and surrounding vehicles, vehicle types, and clearance. The models were estimated using trajectory data collected during medium-flow conditions from an urban arterial in Chennai city, India. The findings from this study have direct implications on modeling lateral shifts in microscopic traffic simulations to be developed specifically for mixed traffic conditions. © 2018 American Society of Civil Engineers.Item GIS-based multi-criteria analysis for identification of potential groundwater recharge zones - a case study from Ponnaniyaru watershed, Tamil Nadu, India(KeAi Communications Co., 2020) Devanantham, D.; Subbarayan, S.; Singh, L.; Jennifer, J.J.; Saranya, T.; Kulithalai Shiyam Sundar, K.S.S.Groundwater is one of the most vital natural resources; spatially varying in quality and quantity. Increased urbanisation and population creates tremendous pressure on the quality and quantity of the groundwater resources. In this study, Ponnaniyaru watershed of Cauvery basin was considered for this research. Geographical information system (GIS) and remote sensing (RS) plays a vital role in preparing various thematic layers for targeting the groundwater potential zones (GWPZ). This study adopts the Analytical Hierarchy Process (AHP) and Multi influence factor (MIF), multi-criteria decision-making approaches to determine the weights for the influencing factors. Weighted linear overlay analysis was carried out to determine the GWPZ. Further, the resultant GWPZ map has been reclassified into five different classes, namely Very good, Good, Moderate, Poor and Very poor. The results were validated with observed well-yield data, and the predictive precision for AHP and MIF was found to be 75%, and 71% respectively. © 2020 The AuthorsItem Identifying Municipal Solid Waste Dumping Site Location Using AHP and GIS Techniques: A Case Study of Coimbatore District, India(Springer, 2022) Aishwarya, V.; Salma, S.; Dodamani, B.M.Increased municipal solid waste generation in urban areas is a result of fast population growth and urbanization. Dumping or landfilling in unsuitable areas becomes the biggest concern for solid waste management authorities. The present dump yard at Vellalore, Coimbatore district, affect nearby settlements with a foul stench and flying ashes due to strong winds. The study’s main goal was to provide alternative landfilling sites in the Coimbatore district using GIS and analytic hierarchy process (AHP) techniques. Nine criteria were considered. These were population density, slope, geology, geomorphology, land use/land cover, and proximity to road, river, railway, and airport. Weighted overlay, a spatial analyst tool that reclassifies raster maps and a final suitability map, is generated. According to the findings, the possible landfill zones were found in the northeastern region of Coimbatore. Hence, the environmentally suitable sites can be selected by using remote sensing and GIS techniques. © 2022, Indian Society of Remote Sensing.Item Coastal vulnerability assessment for the coast of Tamil Nadu, India—a geospatial approach(Springer Science and Business Media Deutschland GmbH, 2023) Devanantham, D.; Subbarayan, S.; Kulithalai Shiyam Sundar, P.A coastal region is a section of land that borders a significant body of water, often the sea or ocean. Despite their productivity, they are sensitive to even little alterations in the outside environment. This study aims to develop a spatial coastal vulnerability index (CVI) map for the Tamil Nadu coast of India, which has diverse coastal and marine environments that are ecologically fragile zones. Climate change is expected to increase the intensity and frequency of severe coastal hazards, such as rising sea levels, cyclones, storm surges, tsunamis, erosion, and accretion, severely impacting local environmental and socio-economic conditions. This research employed expert knowledge, weights, and scores from the analytical hierarchy process (AHP) to create vulnerability maps. The process includes the integration of various parameters such as geomorphology, Land use and land cover (LULC), significant wave height (SWH), rate of sea level rise (SLR), shoreline change (SLC), bathymetry, elevation, and coastal inundation. Based on the results, the very low, low, and moderate vulnerability regions comprise 17.26%, 30.77%, and 23.46%, respectively, whereas the high and very high vulnerability regions comprise 18.20% and 10.28%, respectively. The several locations tend to be high and very high due to land-use patterns and coastal structures, but very few are contributed by geomorphological features. The results are validated by conducting a field survey in a few locations along the coast. Thus, this study establishes a framework for decision-makers to implement climate change adaptation and mitigation actions in coastal zones. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item Multi-Criterion Analysis of Cyclone Risk along the Coast of Tamil Nadu, India—A Geospatial Approach(Multidisciplinary Digital Publishing Institute (MDPI), 2023) Subbarayan, S.; Devanantham, D.; Kulithalai Shiyam Sundar, P.; Reddy, N.M.; Almohamad, H.; Al-Dughairi, A.A.; Al-Mutiry, M.; Abdo, H.G.A tropical cyclone is a significant natural phenomenon that results in substantial socio-economic and environmental damage. These catastrophes impact millions of people every year, with those who live close to coastal areas being particularly affected. With a few coastal cities with large population densities, Tamil Nadu’s coast is the third-most cyclone-prone state in India. This study involves the generation of a cyclone risk map by utilizing four distinct components: hazards, exposure, vulnerability, and mitigation. The study employed a Geographical Information System (GIS) and an Analytical Hierarchical Process (AHP) technique to compute an integrated risk index considering 16 spatial variables. The study was validated by the devastating cyclone GAJA in 2018. The resulting risk assessment shows the cyclone risk is higher in zones 1 and 2 in the study area and emphasizes the variations in mitigation impact on cyclone risk in zones 4 and 5. The risk maps demonstrate that low-lying areas near the coast, comprising about 3%, are perceived as having the adaptive capacity for disaster mitigation and are at heightened risk from cyclones regarding population and assets. The present study can offer valuable guidance for enhancing natural hazard preparedness and mitigation measures in the coastal region of Tamil Nadu. © 2023 by the authors.Item Preparedness for a forgotten disaster: A case study Coimbatore, India(Elsevier Ltd, 2024) Lalith Prakash, E.; Anand, K.B.; Kolathayar, S.Earthquake preparedness is known to effectively reduce the distressful effects of earthquakes, as demonstrated in experiences worldwide. This research aims to use a region-specific, valid, and reliable survey-based tool to assess individual and community earthquake preparedness levels in a densely populated city region with a forgotten earthquake history. The study focuses on evaluating the earthquake preparedness levels of a population in the Indian peninsular shield region that has not experienced an earthquake or received any preparatory program in their life time; but the region has an earthquake history. Coimbatore city was chosen for the same reason, and two survey-based tools were developed - the Individual Earthquake Readiness Index (IERI) and the Community Earthquake Readiness Index (CERI) - using a comprehensive literature analysis, questionnaire creation via focused group discussion followed by expert panel validation, and pilot studies. This study ensured the validity and reliability of the tools through content validity, construct validity, internal consistency test, Spearman's test-retest reliability test, Exploratory Factor Analysis (EFA), and Confirmatory Factor Analysis (CFA). The final IERI is a 27-item tool, and the final CERI is a 20-item tool. This study broadens the scope of risk assessment, facilitating a methodical estimation of Earthquake Readiness Index as one of the pivotal social vulnerability determinant. The study revealed a strong sense of community spirit in Coimbatore, but residents showed a lack of individual preparedness and were hesitant to take leadership roles. The findings emphasize the need for targeted interventions to bridge the gaps in earthquake preparedness, fostering a culture of proactive engagement and individual responsibility. © 2023Item Probabilistic Seismic Hazard Assessment and Liquefaction Potential Evaluation for Amaravati Capital Region(Springer, 2024) Kolathayar, S.; Ashrith, M.S.; Rukminikumar, S.The present study aims to evaluate the seismic hazard and liquefaction potential for Amaravati capital region (16° 4?–16° 49? N and 80° 7?–81° 2? E) using the latest earthquake data and in-situ geotechnical data. A state-of-the-art Probabilistic Seismic hazard assessment was carried out for the region, and PGA values were obtained for Maximum Credible Earthquake (MCE) and Design-Based Earthquake (DBE) levels, which are 2% and 10% probability of exceedance for 50 years corresponding to 2475 and 475 return periods, respectively. The maximum PGA values at the bedrock level obtained were 0.084 g and 0.172 g for DBE and MCE levels, respectively. Borehole data from 16 different locations were used in the analysis. Liquefaction potential was evaluated using the Seed and Idriss method considering SPT-N values at the site. Liquefaction hazard maps were developed for 3 m and 6 m depths for both MCE and DBE levels. It is observed that the Factor of safety (FoS) against Liquefaction is lesser for MCE ground motion, whereas FoS is higher for the DBE levels. The region was found to be safe against liquefaction for design-based earthquakes, whereas the liquefaction potential was found to be high for maximum credible earthquakes. © The Author(s), under exclusive licence to Indian Geotechnical Society 2024.