A Comparative Study of Conventional and Non-Destructive Methods of In-Situ Stress Measurement

Over the past many decades, in-situ stress measurement using overcoring (OC) and hydraulic fracturing (HF) methods has been scientifically accepted and commercially adopted worldwide as the benchmark techniques for quantifying in-situ stress in rock masses. However, with the increase in depth of mining operations, the application of OC and HF has become more cumbersome and costlier, requiring substantial drilling, specialized equipment, and favorable borehole conditions for reliable data collection. This paper investigates the potential of non-destructive techniques (NDTs) for in-situ stress estimation as practical alternatives to conventional methods. A structured comparison of the non-destructive techniques including AE, Deformation Rate Analysis (DRA), Secant Modulus Method (SMM) is presented with the conventional OC and HF methods based on the published literature. To validate these techniques further, non-destructive tests were conducted on oriented rock cores retrieved from a mine site in South Australia where conventional overcoring had been previously applied. The SMM and AE analyses were used to determine the stress tensor and magnitude & direction of principal stresses. The results show a good correlation with the OC data, reinforcing the reliability of NDTs of stress estimation. These findings suggest that integrated non-destructive methods can provide cost-effective alternatives to traditional in-situ stress measurement techniques, offering significant implications for deep mining projects and early-stage stress characterization where borehole access is limited.