Multiscale progressive 3D geological modeling based on isochronous stratigraphy identification in urban underground space

3D geological modeling facilities the visualization of geological conditions to hone engineering decisions in the utilization of urban underground space, but it poses significant challenges due to multiscale application scenarios within different resolutions, as well as complex coupled modeling procedures between geometry and properties. Massive multisource geological data have been collected in Wuhan city. Nevertheless, a regional 3D geological model had not been established yet. To address these issues, a multigrid progressive 3D geological modeling scheme is proposed and then adopted to multiscale progressive 3D geological modeling in Wuhan city. Initially, the geological framework is established with grid division according to the regional geological evolution surveys, and 3D geological structure modeling is subsequently implemented by discrete smooth interpolation method leveraging borehole and synthetic data extracted from geological profiles with nodes identification. Following isochronous stratigraphy features analysis of geological properties and borehole density assessment within grid subdivision, the 3D property model is built using an optimized ordinary kriging method constrained by the multiscale structure model. Finally, the 3D geological model is validated and updated under the multiscale framework in conjunction with new site investigations. The multiscale progressive 3D geological modeling workflow is employed in urban metro construction scenarios, and it paves a way to promote the application of geological survey achievements in the whole life cycle of urban underground space development.