Faculty Publications
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Item Estimation of Rock Strength Properties Using Selected Mechanical Parameters Obtained During the Rotary Drilling(Springer, 2019) Lakshminarayana, C.R.; Tripathi, A.K.; Pal, S.K.During the preliminary stage of rock engineering projects, the estimation of mechanical properties of rocks is most often required. The requirement of a large number of high-quality rock core samples is the major drawback when the mechanical rock properties are to be determined in a well-established rock mechanics laboratory. In this study, an attempt is made to estimate the uniaxial compressive strength and Brazilian tensile strength of sedimentary rocks using the selected mechanical drilling operating parameters obtained during the rotary drilling. The operating measured parameters such as the weight on bit or thrust and the vibration frequency induced at machine or drill head were acquired using the drill tool dynamometer and sound/vibration data acquisition system, respectively. The mathematical models were developed considering the drilling operational parameters (drill bit diameter, drill bit speed and penetration rate) and measured mechanical parameters (thrust and vibration frequency). The prediction potential of the developed models was assessed by the prediction performance indices. The outcome results revealed that the developed mathematical model using the approached method is significant and can be conveniently used for the estimation of mechanical properties of rocks during the rotary drilling. © 2019, The Institution of Engineers (India).Item Prediction of Mechanical Properties of Sedimentary Type Rocks Using Rotary Drilling Parameters(Springer, 2020) Lakshminarayana, C.R.; Tripathi, A.K.; Pal, S.K.The estimation of strength properties of sedimentary rocks is most often needed during the preliminary phase of many rock engineering projects carrying out in sedimentary regions. The main drawback of determining the rock properties in a test center is the requirement of the number of superior quality rock core specimens. In this experimental investigation, the uniaxial compressive strength (UCS) and tensile strength of sedimentary rocks are estimating using well-identified drilling variables and acoustic parameters obtained during the rotary type rock drilling. The drilling variables such as thrust, torque, and vibration parameters are used to develop the mathematical models of strength properties of rock. A drill type dynamometer was used to measure the drilling variables, and the vibration parameter would measure using the NI-9234 data acquisition system. The prediction efficiency of the mathematical model is evaluating using performance indices. Results show that the used experimental method can estimate the considered responses (UCS and tensile strength) with the acceptable percentage errors of 10.52% and 11.27% respectively, and may be useful to measure the UCS and BTS of sedimentary rocks in a laboratory capacity without test core samples. © 2020, Springer Nature Switzerland AG.Item Prediction of thermal conductivity of quartz chlorite schist rocks: a comparative study of MLR and ridge regression(Inderscience Publishers, 2025) Tripathi, A.K.; Pal, S.K.; Dileep, G.; Raj, A.Thermal conductivity is a key physical property with broad applications in engineering and geosciences, particularly in energy-efficient building design, geothermal energy systems, and subsurface geological studies. Accurate determination of thermal conductivity is essential for understanding heat transfer mechanisms in rock materials. However, direct in-situ measurement is often impractical due to technical and logistical constraints. As a result, indirect estimation methods, which establish empirical relationships between thermal conductivity and various physico-mechanical properties, have gained attention. This study investigates the thermal conductivity of quartz chlorite schist through laboratory experiments, alongside measuring key physico-mechanical properties, including P-wave velocity, porosity, density, and uniaxial compressive strength (UCS). The objective is to analyse the correlations between thermal conductivity and these properties to develop a reliable predictive model. Multiple regression and ridge regression analysis are employed to derive an empirical equation for estimating thermal conductivity based on the measured parameters. The findings of this study contribute to improving indirect assessment techniques, which are valuable for geotechnical and geological applications where direct measurements are challenging. © © 2025 Inderscience Enterprises Ltd.