Faculty Publications

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Author: search.filters.author.Vardhan, H.Subject: search.filters.subject.drilling

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    Estimating rock properties using sound levels produced during drilling
    (Elsevier BV, 2009) Vardhan, H.; Adhikari, G.R.; Govinda Raj, M.
    An attempt has been made in this paper to experimentally investigate the estimation of rock properties like compressive strength and abrasivity using sound levels produced during drilling. The investigation was carried out on a laboratory scale using small portable pneumatic drilling equipment used in hard rock drilling. For this purpose, a pneumatic drill setup was fabricated for drilling vertical holes. The compressive strength and the abrasivity of various rock samples collected from the field were determined in the laboratory. A set of test conditions were defined for measurement of sound level of the pneumatic drill. Also, with the help of the experimental setup, vertical drilling was carried out on the rock samples for varying thrust and air pressure values and the corresponding A-weighted equivalent continuous sound levels were measured. Results of this study indicate that sound level can be a promising tool in estimating rock properties during drilling. © 2008 Elsevier Ltd. All rights reserved.
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    Prediction of uniaxial compressive strength, tensile strength and porosity of sedimentary rocks using sound level produced during rotary drilling
    (2011) Rajesh Kumar, B.R.; Vardhan, H.; Govindaraj, M.
    The main purpose of the study is to develop a general prediction model and to investigate the relationships between sound level produced during drilling and physical properties such as uniaxial compressive strength, tensile strength and percentage porosity of sedimentary rocks. The results were evaluated using the multiple regression analysis taking into account the interaction effects of various predictor variables. Predictor variables selected for the multiple regression model are drill bit diameter, drill bit speed, penetration rate and equivalent sound level produced during rotary drilling (Leq). The constructed models were checked using various prediction performance indices. Consequently, it is possible to say that the constructed models can be used for practical purposes. © Springer-Verlag 2011.
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    Sound level produced during rock drilling vis-à-vis rock properties
    (2011) Rajesh Kumar, B.; Vardhan, H.; Govindaraj, M.
    The process of drilling, in general, always produces sound. Though sound is used as a diagnostic tool in mechanical industry, its application in predicting rock property is not much explored. In this study, an attempt has been made to estimate rock properties such as uniaxial compressive strength, Schmidt rebound number and Young's modulus using sound level produced during rotary drilling. For this purpose, a computer numerical controlled vertical milling centre was used for drilling holes with drill bit diameters ranging from 6 to 20. mm with a shank length of 40. mm. Fourteen different rock types were tested. The study was carried out to develop the empirical relations using multiple regression analysis between sound level produced during drilling and rock properties considering the effects of drill bit diameter, drill bit speed and drill bit penetration rate. The F-test was used to check the validity of the developed models. The measured rock property values and the values calculated from the developed regression model are fairly close, indicating that the developed models could be efficiently used with acceptable accuracy in prediction of rock properties. © 2011 Elsevier B.V.
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    A critical review on estimation of rock properties using sound levels produced during rotary drilling
    (CAFET INNOVA Technical Society cafetinnova@gmail.com 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2012) Masood; Vardhan, H.; Mangalpady, M.; Rajesh Kumar, B.
    This paper summarizes the critical review on estimation of rock properties using sound levels produced during rotary drilling. In this paper an overall emphasis has been made to summarize the importance of sound level produced during drilling by considering various parameters like drill bit speed, penetration rate, drill bit diameter, type of drill bit and equivalent sound level produced during drilling for the estimation of rock properties. Further an attempt has also made to include the application of ANN modeling and acoustic emission in estimating rock properties. © 2012 CAFET-INNOVA TECHNICAL SOCIETY.
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    Prediction of penetration rate and sound level produced during percussive drilling using regression and artificial neural network
    (2012) Kivade, S.B.; Murthy, C.S.N.; Vardhan, H.
    The main objective of this investigation is to develop a general prediction model and to study the effect of predictor variables such as uniaxial compressive strength, air pressure and thrust on penetration rate and sound level produced during percussive drilling of rocks. The experiment was carried out using three levels Box-Behnken design with full replication in 15 trials. Modeling was done using artificial neural network (ANN) and multipleregression analysis (MRA). These techniques can be utilized for the prediction of process parameters. Comparison of artificial neural network and multiple linear regression models was made and found that error rate was smaller in ANN than that predicted by MRA in terms of sound level and penetration rate. © 2012 CAFET-INNOVA TECHNICAL SOCIETY.
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    Regression analysis and ANN models to predict rock properties from sound levels produced during drilling
    (Elsevier Ltd, 2013) Rajesh Kumar, B.; Vardhan, H.; Govindaraj, M.; Vijay, G.S.
    This study aims to predict rock properties using soft computing techniques such as multiple regression, artificial neural network (MLP and RBF) models, taking drill bit speed, penetration rate, drill bit diameter and equivalent sound level produced during drilling as the input parameters. A database of 448 cases were tested for determination of uniaxial compressive strength (UCS), Schmidt rebound number (SRN), dry density (?), P-wave velocity (Vp), tensile strength (TS), modulus of elasticity (E) and percentage porosity (n) and the prediction capabilities of the models were then analyzed. Results from the analysis demonstrate that neural network approach is efficient when compared to statistical analysis in predicting rock properties from the sound level produced during drilling. © 2012 Elsevier Ltd.
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    Artificial neural network model for prediction of rock properties from sound level produced during drilling
    (2013) Rajesh Kumar, B.; Vardhan, H.; Govindaraj, M.; Saraswathi, P.S.
    In many rock engineering applications such as foundations, slopes and tunnels, the intact rock properties are not actually determined by laboratory tests, due to the requirements of high quality core samples and sophisticated test equipments. Thus, predicting the rock properties by using empirical equations has been an attractive research topic relating to rock engineering practice for many years. Soft computing techniques are now being used as alternative statistical tools. In this study, artificial neural network models were developed to predict the rock properties of the intact rock, by using sound level produced during rock drilling. A database of 832 datasets, including drill bit diameter, drill bit speed, penetration rate of the drill bit and equivalent sound level (Leq) produced during drilling for input parameters, and uniaxial compressive strength (UCS), Schmidt rebound number (SRN), dry density (?), P-wave velocity (Vp), tensile strength (TS), modulus of elasticity (E) and percentage porosity (n) of intact rock for output, was established. The constructed models were checked using various prediction performance indices. Goodness of the fit measures revealed that recommended ANN model fitted the data as accurately as experimental results, indicating the usefulness of artificial neural networks in predicting rock properties. © 2013 Copyright Taylor and Francis Group, LLC.
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    Portable low cost drill set-up for estimating rock properties
    (CAFET INNOVA Technical Society cafetinnova@gmail.com 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2014) Masood; Vardhan, H.; Mangalpady, M.
    The mechanical strength of rock is one of the most important factors of concern to engineers involved in mining operations. Information about rock strength is used in rock excavation planning and design operations in civil and mining engineering. Drilling is widely carried out in hard rock’s for blasting the rock mass so that the blasted material can be easily loaded by the excavators. The drillability of rock depends on many factors including rock properties. Whereas properties such as compressive strength, porosity, density etc. are uncontrollable parameters during drilling process. A number of studies have been reported recently on the application of sound level, which have been concentrated on using either CNC or jack hammer machine for drilling purpose. It is worth mentioning that neither CNC machine nor jack hammer drill set-up is the normal way of drilling in rock, nor in mining, civil or any other operations, not even in working with rock in installation of countertops. Therefore, it is difficult to exactly say whether the noise generated during drilling is only from the rock drilling or from the drilling unit itself. In view of the above, it is important to fabricate a new drilling set-up which is a silent unit in itself. Such unit when used for drilling purpose will clearly indicate the change in sound level produced with different rock properties. © 2014 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Estimating rock properties using sound signal dominant frequencies during diamond core drilling operations
    (Chinese Academy of Sciences rockgeotech@whrsm.ac.cn, 2019) Vijaya Kumar, C.V.; Vardhan, H.; Murthy, C.S.N.; Karmakar, N.C.
    In many engineering applications such as mining, geotechnical and petroleum industries, drilling operation is widely used. The drilling operation produces sound by-product, which could be helpful for preliminary estimation of the rock properties. Nevertheless, determination of rock properties is very difficult by the conventional methods in terms of high accuracy, and thus it is expensive and time-consuming. In this context, a new technique was developed based on the estimation of rock properties using dominant frequencies from sound pressure level generated during diamond core drilling operations. First, sound pressure level was recorded and sound signals of these sound frequencies were analyzed using fast Fourier transform (FFT). Rock drilling experiments were performed on five different types of rock samples using computer numerical control (CNC) drilling machine BMV 45 T20. Using simple linear regression analysis, mathematical equations were developed for various rock properties, i.e. uniaxial compressive strength, Brazilian tensile strength, density, and dominant frequencies of sound pressure level. The developed models can be utilized at early stage of design to predict rock properties. © 2019 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences
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    Multiple regression model for prediction of rock properties using acoustic frequency during core drilling operations
    (Taylor and Francis Ltd., 2020) Vijaya Kumar, V.; Vardhan, H.; Murthy, C.S.N.
    The primary purpose of this study is the quantification of rock properties uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), density and abrasivity, using sound signal dominant frequencies produced during diamond core drilling operations. Rock drilling operations were performed on seven different types of rock samples, using a computer numerical control (CNC) drilling machine. Using the multiple regression analysis, satisfactory mathematical equations were developed for various physico-mechanical rock properties, as well as dominant frequencies of the sound level were generated during diamond core drilling operations. The developed prediction models demonstrated a good regression coefficient between the rock properties and dominant frequencies i.e. the R2 values are 82.50%, 78.41%, 79.40%, and 93.24% for UCS, BTS, density and abrasivity, respectively. The performances indices are: (i) root-mean-square error (RMSE) are 0.102754, 1.241652, 0.396727, and 0.697889 for UCS, BTS, density and abrasivity, respectively; (ii) values account for (VAF) is 82.50008%, 78.41137%, 79.40137%, and 93.23596% for UCS, BTS, density and abrasivity, respectively. Presently, it is in the early stages of development towards the prediction of rock properties using dominant frequencies with the help of audio signal processing in the rock drilling operation. The developed prediction models can be utilised at the early stages of mining and civil engineering projects, for the quantification of rock properties using sound signal dominant frequencies. © 2019 Informa UK Limited, trading as Taylor & Francis Group.