Abstract:Accurate in situ recognition of rock structural interfaces during coring drilling is essential for refined rock-mass characterization and engineering stability assessment, yet remains difficult because drilling responses are multivariate, noisy, and spatially distributed. This study proposes a mechanism-constrained framework for structural-interface recognition by reconceptualizing interface penetration as a progressive drilling-disturbance process rather than a single-point anomaly. Thrust force, torque, penetration per revolution, and mechanical specific energy were integrated into a fused response representation for interface localization. On this basis, a hierarchical indicator system consisting of three primary indicators and three secondary mechanistic indicators was established for interface-type discrimination and mechanistic interpretation. A two-stage identification strategy was further introduced to improve robustness under fluctuating drilling conditions and heterogeneous interface responses. The framework was evaluated using both designed laboratory specimens and irregular field specimens, while independent image-based analysis was used as geometric reference for validation. The results show that the proposed method achieved localization errors below 2% for designed laboratory interfaces and below 6% for irregular field specimens, while revealing systematic differences in the disturbance structures of natural, grooved, cemented, and coupled interfaces. Image-based results further suggest that the mechanically disturbed zone may extend beyond the visible geometric boundary. These findings demonstrate that the proposed framework provides a robust and interpretable basis for drilling-based structural-interface localization, type recognition, and mechanism-oriented analysis.

Measurement while drilling (MWD); Rock structural interface; Multi-parameter fusion; Hierarchical indicator framework; Two-stage identification; Image-space validation