Abstract: Design of tree topology cavern project often faces the challenges of multidiscipline, multipipeline, multiintersection, multisection, etc.  Relying on a cavern project, the main points of building information modeling (BIM) technology are summarized, and through Revit and Navisworks software platform, 3D modeling technical route and process of cavern project are sorted out and defined. The 3D modeling method of some complex structures like parametric arch ring, room joint and Yjoint is mainly studied, which solves the problems of mismatch between pipeline and reserved buried pipeline, conflict between buried pipeline and bottom pit, and pipeline passing stress component of vault. The practical results show that: (1) The efficiency of section selection in digital design is greatly improved by realizing a family of common arch contour parameterization. (2) The visualization characteristics of BIM software and the principle of collision interference check provide theoretical support for the selection of complex structures such as room joints and Yjoint, and effectively avoids design error and omission. (3) Based on the geometric information and attribute information of components, some volume statistics and 2D diagram can be generated automatically, which significantly improves the design and delivery efficiency.

Key words: building information modeling, tree topology structure, cavern, threedimensional design, modeling process, collision check