Evaluation of the Diametrical Core Deformation Analysis (DCDA) and Fracture Surface Morphology for In-Situ Stress Estimation

In-situ stress is a crucial parameter for the design and construction of underground engineering structures. However, accurately and efficiently determining the stress state has long been challenging, especially in deep boreholes where core discing occurs under high stress. In this study, we focus on an in-situ stress estimation method based on Diametrical Core Deformation Analysis (DCDA) to measure stress at a depth of 500 m in the monzonitic granite of North Tianshan Mountains, Xinjiang, China. Using this approach, we measured the diameter of 20 rock core samples with a maximum resolution of 1.2 mu m and integrated laser scanning with ArcGIS to quantitatively characterize fracture surface morphology. Our findings indicate that the magnitude of in-situ stress derived from core samples using DCDA aligns well with hydraulic fracturing results. Additionally, stress orientation in the plane perpendicular to the drill axis can be inferred from the morphological anisotropy of the fracture surfaces. The research demonstrates that the minimum principal stress orientation estimated by DCDA is consistent with the observed morphology of discing fractures. Furthermore, we found that reliable stress estimation requires not only high-resolution datasets but also accurate assessments of local rock mechanical parameters and their potential anisotropy.