Predicting the Geomechanical Properties of Hard Rocks Using Analysis of the Acoustic and Vibration Signals During the Drilling Operation

Evaluating the physical and mechanical properties of materials such as rock or concrete is among the most significant issues in engineering studies. Measurement of the properties of the rocks either in the laboratory or in the field needs the standards and specific methods. Also, most of these tests need time and a large number of rock samples. Therefore, finding a method that can be accurately, quickly, and reliably predict the properties of rocks will provide a great advance in the quality of studies before or during the projects. The purpose of this paper is to find a method for predicting and determining the geomechanical properties of hard rocks during the drilling operation. For this purpose, after the preparation of the rock samples, acoustic and vibration signals propagated during the drilling process were recorded and processed. After analysing the acoustic and vibration signals, statistical analysis for investigation of the relationship between the properties of the rocks and the acoustic parameters was performed. Sound Pressure Level (SPL), First Dominant Frequency (FDF), and Vibration Level (VL) were selected as predictor variables for measuring and predicting Uniaxial Compressive Strength (UCS), Brazilian Tensile strength (BTS) and Schmidt rebound number (SRN) by multivariable regression. Results of statistical analysis show that there is an acceptable correlation coefficient between rock properties and properties of acoustic and vibration signals of the rock drilling operation. Hence, this method can be used as a relatively inexpensive, non-destructive, reliable and real-time method in large-scale mining or civil operation for predicting the rock properties.