Assessment of the integrated DRA-AE method for in-situ stress measurement under uniaxial cyclic loading

Abstract

Indirect methods for measuring in-situ stress, including deformation rate analysis (DRA) and acoustic emission (AE), have attracted considerable research interest because they are simple to implement and cost-effective. In this study, rock cores were obtained from three horizontal boreholes separated by 45° in azimuth at each mining level to determine the tectonic stress. Uniaxial cyclic loading–unloading tests were conducted on magnetite and marble specimens. DRA turning points were identified from strain-difference curves using hyperbolic linear regression. Kaiser effect points were identified from the absolute AE energy and cumulative counts and were subsequently validated by evaluating the Felicity effect. At the − 146 m level, the maximum and minimum horizontal principal stresses were 21.85 and 14.47 MPa, respectively; at the − 196 m level, the corresponding values were 21.04 and 15.49 MPa. The estimates obtained using the two methods were in close agreement. Bland–Altman analysis showed that 90% of the paired measurements fell within the 95% limits of agreement, while linear regression yielded an R 2 of 0.9666, indicating strong statistical consistency between the two laboratory methods. Integrating DRA and AE therefore improves the reliability of indirect in-situ stress determination and has considerable potential for engineering applications.