Browsing by Author "Hegde, R."

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Accelerated consolidation of coir reinforced lithomargic laterite soil blends with vertical sand drains for pavements
(2012) George, V.; Hegde, R.; Vardhana, M.V.; Santosh, G.; Gotamey, D.
It is found that sub-grade soils of lateritic origin encountered in the construction of highway embankments in various regions of India, often comprise intrusions of soft lithomargic soils that result in large settlements during constructions, and differential settlements at later stages. This necessitates the use of appropriate soil improvement techniques to improve the load-carrying capacity of pavements. This work deals with the accelerated consolidation of un-reinforced and coir-reinforced laterite and blended lithomargic soils, provided with three vertical sand drains. The load-settlement characteristics were studied for various preloads ranging from 50kg (0.0013 N/mm2) to 500kg (0.013N/mm2). Studies were performed using circular ferro-cement moulds. It was observed that at lower preloads of up to 250kg, the relative increase in consolidation (Rct) for randomly reinforced soil with vertical drains was significantly higher than that of un-reinforced soil without vertical drains. Also, the Rct for un-reinforced soil with vertical drains was quite higher than that of un-reinforced soil without vertical drains, with an average value of 20.84%. In the case of higher preloads the Rct values for randomly reinforced soil with vertical drains were moderate with an average value of 22.67%. An additional increase of up to 27% at lower pre-loads and 11.83% at higher pre-loads was observed due to the effect of random reinforcement when compared to use of vertical drains alone. 2012 ejge.
Critical heat flux enhancement in pool boiling using alumina nanofluids
(2010) Hegde, R.; Rao, S.S.; Reddy, R.P.
The pool boiling characteristics of dilute dispersions of alumina nanoparticles in water were studied. Consistent with other nanofluid studies, it was found that a significant enhancement in critical heat flux (CHF) can be achieved at modest nanoparticle concentrations (<0.1% by volume). During experimentation and subsequent inspection, formation of a porous layer of nanoparticles on the heater surface occurred during nucleate boiling. This layer significantly changes surface texture of the heater wire surface which could be the reason for improvement in the CHF value. 2010 Wiley Periodicals, Inc.
Deterministic Seismic Hazard Analysis of Sree Padmanabhaswamy Temple, Kerala State
(Springer, 2025) Padmanabhan, M.P.H.; Siddhardha, R.; Kolathayar, S.; Hegde, R.; Beekanahalli Mokshanatha, B.M.
Deterministic seismic hazard analysis (DSHA) is a technique employed to estimate potential hazards and ground shaking resulting from specific earthquake scenarios at a given location. In the present study, DSHA is conducted for the Sree Padmanabhaswamy Temple, situated in the southernmost district of Kerala, India. This seismic hazard study is crucial due to the temple’s proximity to seismic events such as the 1900 AD Coimbatore earthquake with a magnitude of 6.3 Mw and the 2000 Pala earthquake with a magnitude of 4.7 Mw. This study examines earthquake data within a 500 km radius surrounding the Sree Padmanabhaswamy Temple in Thiruvananthapuram District, Kerala, from 1819 to 2022 AD. The seismic zone of the temple site is III according to the Indian zonation map (IS 1893 (Part 1): 2016), relying on past earthquakes recorded throughout India. The collected earthquake data underwent a homogenization process to determine the moment magnitude (Mw), distinguishing foreshocks and aftershocks from the main shocks. A seismotectonic map was developed comprising of geological discontinuities and 316 earthquakes events with moment magnitudes between 3.0 and 6.3 Mw. The software tools employed for this work include MATLAB, QGIS and ZMAP. The Log-likelihood technique (LLH) was used to choose the ground motion prediction equations (GMPEs) for the location. The GMPEs were then given weights based on the computed values of the data support index (DSI). The study region was partitioned into a grid size of 0.05° × 0.05° (5 km × 5 km). Using MATLAB code, the peak ground acceleration (PGA) was estimated for the site and PGA was found in the center of each grid cell, taking into account all seismic sources within a 500 km radius. In addition, site-specific deterministic spectrum was also developed. The findings show that Sree Padmanabhaswamy Temple has low seismicity, which is defined by weak to moderate earthquakes that have sources close to the temple. © The Author(s), under exclusive licence to Indian Geotechnical Society 2024.
A model study on accelerated consolidation of coir reinforced laterite and blended shedi soil with vertical sand drains for pavement foundations
(2012) George, V.; Santosh, G.; Hegde, R.; Durga, Prashanth, L.; Gotamey, D.; Ravi, Sankar, A.U.
Sub-grade soils of lateritic origin are frequently encountered in the construction of highway embankments in various regions of India, often comprise intrusions of soft lithomargic soils that result in large settlements during constructions, and differential settlements at later stages. This necessitates the use of appropriate soil improvement techniques to improve the load-carrying capacity of pavements. Coir is a natural fiber that can be used in place of geosynthetics and geogrids, and it is biodegradable and environment friendly. This work deals with the accelerated consolidation of un-reinforced and coir-reinforced laterite and blended lithomargic soils, provided with three vertical sand drains. The load-settlement characteristics were studied for various preloads ranging from 50kg (0.0013 N/mm2) to 500kg (0.013N/mm2) using circular ferro-cement moulds. It was observed that at lower preloads up to 300kg, the relative increase in consolidation (Cr) for randomly reinforced soil with vertical drains was significantly higher than that of un-reinforced soil without vertical drains. Also, the Cr for un-reinforced soil with vertical drains was quite higher than that of un-reinforced soil without vertical drains, with values above 38.71%. However, in the case of higher preloads of 450kg and 500kg, the Cr for randomly reinforced soil with vertical drains was insignificant, and the Cr for un-reinforced soil with vertical drains remained slightly higher at around 9.59% for similar comparisons. The aspect-ratio of coir fibers used was 1: 275. 2012 Cafet-Innova Technical Society. All rights reserved.
Statistical Analysis of Seismicity Parameters and Completeness Period of Earthquake Catalog for Sree Padmanabhaswamy Temple, Thiruvananthapuram District, Kerala
(Springer Science and Business Media Deutschland GmbH, 2023) Padmanabhan, M.P.H.; Siddhardha, R.; Kolathayar, S.; Hegde, R.
In the present study, seismicity data analysis of Sree Padmanabhaswamy Temple, Thiruvananthapuram District, Kerala, India, has been performed. The area is having a radius of 500Â km with Sree Padmanabhaswamy Temple (8.48Â°N Latitude and 76.94Â°E Longitude) as the center. Earthquake catalog from 1822 to 2021 has been compiled and homogenized into equivalent moment magnitude (Mw) using regional empirical relationships. Data on earthquakes were declustered usingÂ Urhammer method to exclude foreshocks and aftershocks within a time and space window, and then statistical analysis was done to ensure data completeness. Using theÂ Guntenberg-Ritchers recurrence relationship, the seismic parameters obtained are 1.234 and 0.532, respectively. The Mmax value calculated using Kijkoâ€™s MATLAB algorithm found to be 6.08 Â± 0.26. Â© 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.