Integrated Geo-Objects 3D Modeling, Spatial Analysis Methods And Applications

In urban underground space engineering, geological survey and geotechnical engineering, mining exploration and exploitation engineering, we often deal with various types of geological and mining spatial entities, such as natural entities (e.g. stratum, fault, ore body, country rock etc.), artificial entities (e.g. open pit, tunnel, subway etc.). Currently, independent and static modeling and visualization methods are adopted to reconstruct 3D models of geo-entities, by which geometrical and sematic relationships between different types of models cannot be constructed. These kinds of modeling methods can hardly satisfy engineering application demands of geological and mining design and analysis, such as integrated open pit design, dynamic excavation analysis and dangerous rock mass early warning etc.Therefore, theories and methods for 3D geo-objects integrated modeling, spatial analysis and application technologies based on geo-entity model have become frontier topics of several geosciences domains such as digital mine, digital city and digital geotechnical engineering, and also an intersected hot-spot of 3D geographical information technology, virtual reality technology in city, mine and geology applications. In this paper, orienting to demands of mining and geology engineering applications, we mainly conducted researches and application experiments on integrating methods, dynamic updating technology, multi-scale grid transformation and representation, topological spatial relationship analysis for geo-objects. The main research contents and progresses of this paper are listed below:(1) Based on spatial cognition theory, spatial entities in typical geological and mining environments were firstly classified by their characteristics; then, geological and mining source data were classified according to different kinds of source and adoption methods. Based on classifications of geo-entity and source data, different types of data source for city and mine 3D spatial modeling were introduced. Lastly, the data structure design and pre-processing methods for two kinds of typical source data (exploration borehole and geological section) were introduced in detail.(2) Geological and mining 3D spatial modeling were classified according to different application targets and data sources; the difference between 3D design and reconstruction were presented; the concept and connotation of geological and mining spatial entity modeling were improved; modeling methods classification system of designed entities and measured entities were generalized and abstracted. After the analysis on practical significance and methods status of 3D integrated geo-objects modeling, a novel method for model integration and update based on 3D Boolean operations was adopted, which can be widely adapted to different kinds of 3D vector spatial data models, which are composed of fundamental triangles. This method contains 3D Boolean operations between binary volumes, binary surfaces, binary surface and volume model. This 3D integrated modeling method were applied to practical engineering examples, such as integrated open pit design, rock pit excavation simulation and split analysis of ore bodies.(3) Orienting to 3D grid unit generation demands in mine resources estimation and geotechnical finite element analysis, a ternary axes scan algorithm (TAS) for 3D grid tessellation was proposed to resolve the vector-grid transformation problem for complex geo-entity model. Based on TAS, a parallel TAS algorithm (P-TAS), which can run on the new multi-core CPU and high performance computer cluster, was designed for transforming 3D vector model to grid model with Octree structure, using MPI parallel techniques, which resolved the multi-scale tessellation for the surface and interior of geo-entity model with high performance. Furthermore, the Boolean algorithm for 3D geo-entities represented with multi-scale grid was designed for simulation of underground engineering excavation and dynamic mining exploration process.(4) Orienting to application demands of topological spatial relationship analysis for geo-entities, the theoretical foundation and application availability of topological spatial relationship research for three dimensional geo-entities in raster space are discussed. Based on digital topology theory and 9-1 topological analysis framework, the characteristic, definition and representation methods of the interior, boundary and k-order neighborhoods are proposed furthermore. By expanding topological analysis 9-1 model from vector to raster and from 2D to 3D, a new 9-intersection model named as k-order 6 neighborhoods model (K6N9-I) was proposed, which can be applied to topological analysis for 3D raster entity. Twelve typical topological relations and sixty possible topological relations defined by K6N9-I model were enumerated in detail. The computation method for topological query and analysis based on relation database query language SQL (Structured Query Language) was introduced, and the qualitative representation and the quantitative computation methods of geo-entity's topological relations in 3D raster space are realized in the experimental software.(5) Based on serials of methods on model integration and update,3D vector-raster transformation and representation, topological spatial analysis for geo-objects proposed in this paper, the object oriented analysis and 3D visualized software design technology were adopted in developing the fundamental platform for 3D integrated modeling software. Orienting to city geology and mine application demands, two application software were developed for geotechnical and mining integrated modeling and analysis. The software schema, user interface and typical functions were introduced. Several practical application examples of metal mine, coal mine and geotechnical engineering integrated modeling and analysis were introduced. Three typical applications, including lane roof different rock mass 3D modeling and stability analysis, underground excavation engineering dynamic tunneling simulation, geotechnical engineering pit design and excavation earthwork computation, were introduced in detail.