Traditional three-dimensional(3D)forward design for shield tunnels faces challenges such as the disconnect between geological and structural models,low modeling and simulation efficiency,and significant data loss across systems.Thus,the authors propose a 3D stratigraphic modeling method that utilizes automated stratigraphic sequence definition and sub-borehole recursion to enable differentiated geological models for different tunnel regions.This approach includes a coupling method for aligning 3D geological and structural tunnel models through Boolean operations and virtual borehole probes,alongside methods for automated extraction of geometric boundaries and finite element mesh reconstruction.A two-dimensional(2D)automatic mapping process based on 3D refined geometrical models and contour picking is also introduced.The developed unified platform integrates these methods into a comprehensive shield tunnel 3D parametric design system,termed FDP-ST3D.FDP-ST3D supports 3D geological modeling,structural design,numerical analysis,and automated drawing.Applied successfully in projects including the Jinan metro line S1,the Suzhou rail transit line S1,the shield section of Shenzhen Mawan cross-sea tunnel,and the Sutong GIL utility tunnel,FDP-ST3D demonstrates high data transfer accuracy and reusability,reducing 2D tube sheet drawing time to only 15 min,which significantly improves the design efficiency and accuracy compared with the manual work.