Faculty Publications
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Item Laboratory Investigations on Percussive Drilling(Springer India sanjiv.goswami@springer.co.in, 2013) Kivade, S.B.; Murthy, C.S.N.; Vardhan, H.The laboratory investigation was carried out on ten rock samples using pneumatic drill with drill bits of different diameters. In general, the process of drilling always produces sound. Sound is generated from the bit-rock interface regardless of the material of the bit used in drilling. The predicted sound level and penetration rate are a product of the drill power and the physical properties of the rocks penetrated. Rock samples were collected from the field and physical properties of the rocks were determined in the laboratory. The sound level and penetration rates were correlated with the rock properties. The compressive strength and abrasivity exhibit strong correlations with the sound level and penetration rate. It was concluded that, among the rock properties included in this study, the compressive strength and abrasivity values are the dominant ones affecting the penetration rate and sound level of percussive drills. Though ten rock samples have been covered in this study, detailed analysis of only one of them is presented. © 2013, The Institution of Engineers (India).Item Influence of index angle on specific energy in rock indentation test(CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2015) Kalyan, B.; Murthy, C.S.N.; Choudhary, R.P.In the present work, static indentation tests were carried out in six types of rocks namely pink marble, limestone, basalt, steel gray granite, moon white granite and black galaxy granite using commercial drill bits of 35mm, 38mm, 45mm, 48mm diameters, aimed to know the influence of index (rotation)angle on specific energy. From the experimental data, Force-Penetration (F-P) curves were plotted and Specific energy (energy necessary to excavate a unit volume of rock) values were calculated from F-P curves for each bit rock combinations. The specific energies for the rocks (pink marble, limestone) at 30° index angle were found to be much less than the specific energies at other index angles. Similarly the specific energies for the rocks (basalt, steel gray granite, moon white granite and black galaxy granite) at 20° index angle were found to be much less than the specific energies at other index angles. © 2015 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.Item ANN Models for Prediction of Sound and Penetration Rate in Percussive Drilling(Springer India sanjiv.goswami@springer.co.in, 2015) Kivade, S.B.; Murthy, C.S.N.; Vardhan, H.In the recent years, new techniques such as; Artificial Neural Network (ANN) were employed for developing of the predictive models to estimate the needed parameters. Soft computing techniques are now being used as alternate statistical tool. In this study, ANN models were developed to predict rock properties of sedimentary rock, by using penetration and sound level produced during percussive drilling. The data generated in the laboratory investigation was utilized for the development of ANN models for predicting rock properties like, uniaxial compressive strength, abrasivity, tensile strength, and Schmidt rebound number using air pressure, thrust, bit diameter, penetration rate and sound level. Further, ANN models were also developed for predicting penetration rate and sound level using air pressure, thrust, bit diameter and rock properties as input parameters. The constructed models were checked using various prediction performance indices. ANN models were more acceptable for predicting rock properties. © 2015, The Institution of Engineers (India).Item Prediction of cuttability from rock cutting resistance(South African Institute of Mining and Metallurgy, 2018) Raghavan, V.; Murthy, C.S.N.The objective of this investigation is to predict rock cuttability from measurements of rock cutting resistance (RCR) during the cutting process and to study the influence of mechanical properties on the depth of cut achieved. Point attack bits with angles of 45°, 50°, 55°, and 65° were used and the experiments were conducted at attack angles of 45°, 55°, and 65°, keeping the rotation speed constant while varying the cutting force and torque during cutting. The depth of each cut was measured and the cut material collected and weighed. The experimental data were compared using an artificial neural network (ANN) and finite element method (FEM) to predict RCR for the measured depth of cut. The results reveal that a 55° attack angle produced the optimum depth of cut. © The Southern African Institute of Mining and Metallurgy, 2018.Item Quantification of Rock Properties Using Frequency Analysis During Diamond Core Drilling Operations(Springer, 2019) Vijaya Kumar, C.; Vardhan, H.; Murthy, C.S.N.Rock drilling is one of the most essential operations in mining and allied industries. This study focuses on the quantification of physico-mechanical rock properties using dominant frequencies from the sound signal generated through diamond core drilling operations. The rock drilling experiments were performed on five different types of rock samples using a computer numerical control drilling machine. Using simple linear regression analysis, satisfactory mathematical equations were developed between various physico-mechanical rock properties, namely, uniaxial compressive strength, Brazilian tensile strength, density and dominant frequencies of sound level were generated during diamond core drilling operations. The developed models can be utilised for quantification of rock properties with an acceptable degree of accuracy in realistic applications. © 2019, The Institution of Engineers (India).Item A review study of thermal conductivity and influencing physico-mechanical properties of rocks(Inderscience Publishers, 2023) Dileep, G.; Tripathi, A.K.; Murthy, C.S.N.; Pal, S.K.Geothermal exploration and heat flow studies rely heavily on rock's thermal conductivity, and it controls the subsurface temperature distribution. A broad study of rock thermal properties has become progressively indispensable for geotechnical, civil, mining, and tunnel engineers. The thermal properties of rocks are essential to the ground modification technique of geothermal heat pumps, environmentally conscious projects like dumping high-level nuclear waste in underground sites, and a wide range of engineering projects. The steady-state technique is commonly employed for homogeneous materials, providing a more precise thermal conductivity value despite longer testing times. Conversely, the transient technique is preferred for heterogeneous materials with moisture content, considering this factor but requiring multiple tests to achieve accurate results. This paper explores the predominant approaches used to measure rock thermal conductivity and identify the factors that influence it. Additionally, researchers present a generic equation for predicting the thermal conductivity of rocks using data they have gathered. According to this article, the thermal conductivity of rocks is influenced by several factors such as porosity, density, pressure, moisture content, variations in mineral composition, temperature, and more. © 2023 Inderscience Enterprises Ltd.