Three-dimensional urban geological modeling and its applications

Three-dimensional (3D) urban geological models (3DUGMS) are a very important support for urban planning, construction and management, for they can reduce the blindness in geological cognition and the huge risk in underground engineering design and construction with the representation of spatial structure and relationships of geological objects and phenomena. This paper firstly divides the data in 3D urban geological modeling (3DUGM) into six types: the source data in modeling, 3D geological structure models, 3D geological property models, 3D urban buildings and structures, Digital Elevation Models, 3D thematic surface models. Add then, the characteristics of these models, such as multi-element, multi-thematic, multi-dimensional, multi-scale, massive data, complex data association, are all analyzed in detail. Furthermore, based on the characteristics of every kind of models, we discuss their modeling methods. Specially, an emphasis is given for 3D urban geological structure modeling, of which the architecture, including the modeling methods, dynamic and incremental model updating, model smoothing and optimization, model uncertainty analysis and quality control, the integrated and collaborative visualization and analysis of massive model data, is presented in detail. At last, three models at the plain area, Tongzhou new region and CBD business district in Beijing are presented for showing the effective applications of 3DUGMS in the urban planning and construction.