深部地质岩心饼化现象及形成机理OA

During the process of coring in deep high-stress strata,the core exhibits significant disk-shaped damage characteristics due to disturbance and stress release effects.In this paper,taking the drilling sam-ples from Triassic strata in Sichuan Basin at a depth of 1800 m as the research object,through a combina-tion of macroscopic observation and microscopic analysis,the differences in the disk-shaped damage of shallow and deep surrounding rock cores and their formation mechanisms have been systematically re-vealled.It is found that the non-uniform disk-shaped damage characteristics of shallow cores are domina-ted by the random damage effect caused by drilling and blasting disturbance,while the uniform thin disk-shaped damage of deep cores reflects the intrinsic effect of in-situ stress release.In addition,the diameter of the borehole and the grain characteristics of the core have a significant impact on the disk-shaped dam-age behavior,with larger diameter boreholes and coarser-grained cores more likely to form thicker disk-shaped damaged cores.Through quantitative analysis of cross experiments of numerical simulation,differ-ent effects of horizontal and vertical stresses on crack propagation and energy evolution have been re-vealled,and close relationship between the disk-shaped damage phenomenon and in-situ stress condi-tions have been verified.The study clarifies that the horizontal stress significantly promotes crack propaga-tion,while the vertical stress has a certain inhibitory effect on the disk-shaped damage phenomenon.The core disk-shaped damage phenomenon and its stress characteristics from macroscopic damage morphology to microscopic mechanism have been explained.It will provide insights and technical optimization sugges-tions for deep geological drilling and resource development engineering.