Work

Three-dimensional in situ stress reconstruction in deep hard rock by integrated DCDA–DSA inversion of oriented cores

Year: 2026

Type: article

Abstract: Core-based observables constrain different components of the three-dimensional (3D) in situ stress state in deep hard-rock engineering and therefore require consistent integration. A closed-form DCDA–DSA inversion was developed in which diametrical core deformation analysis (DCDA) provides a dimensional horizontal differential-stress constraint and local stress axis, differential strain analysis (DSA) provides normalized effective principal-stress ratios, and oriented-core reorientation supplies the geographic reference. Four oriented granite cores from 1286.3 to 1304.6 m in the Ruihai deep gold mine each underwent four independent DCDA remounts; the DSA high-pressure interval was selected using dataset-level linearity and derivative-stability criteria. Four-remount mean DCDA differential stresses were 24.36–26.38 MPa, and reconstructed maximum-horizontal-stress axes were 292.33°–315.79°. DSA yielded q H = 1.768–1.815 and q h = 0.637–0.653 with q v = 1; these ratios changed by no more than 0.135% across 18–22 MPa lower fitting bounds. The coupled solution gave σ H = 50.39–53.77 MPa, σ v = 33.78–35.27 MPa, and σ h = 26.03–27.39 MPa, indicating a strike-slip regime. Source-resolved analysis distinguished statistical intervals from processing and elastic-scale sensitivities without imposing an omnibus confidence interval. Reconstructed horizontal stresses showed interval-scale consistency with two independent hydraulic-fracturing tests, and σ v differed from the independent density-log-derived overburden estimate of 34.24 MPa by 1.35%–3.01%. The results provide case-based evidence for a practical core-based complement to field stress measurements in relatively intact deep granite.

Source: International Journal of Rock Mechanics and Mining Sciences

DOI: 10.1016/j.ijrmms.2026.106736