MWD technique to estimate the uniaxial compressive strength of rocks

Abstract

The measurement of mechanical properties of rocks is an essential task to be carried out during the projects involving the rock engineering activities such as civil constructions, tunneling, excavations etc. Although the quantification of uniaxial compressive strength in the laboratory is much faithful, the availability of rock samples and their preparation according to ISRM standards is the major limitation. In this experimental investigation, the quantification of the uniaxial compressive strength (UCS) of rocks using the measurement while drilling (MWD) technique was attempted. During the drilling of dissimilar strength rocks for various combinations of drilling operational parameters, the value of thrust and torque were collected using the digital type drilling dynamometer. The prediction of the UCS was performed by developing a mathematical model considering the parameters used for operating the machine and corresponding thrust and torque values. The prediction capacity of developed model was evaluated using the value account for (VAF), root mean square error (RMSE) and mean absolute percentage error (MAPE). From the results it was concluded that the MWD technique could be a prominent tool for estimation of rock strength properties in future.