Research On 3D Visual Analysis Theory And Application For Complex Engineering Geologic Information

Due to the complicated geological structure and huge related information, great difficulties have been encountered during the engineering design of large-scale hydraulic projects. Traditional explanations and analysis for engineering geologic data were restricted to 2D and static mode. It has been hard to satisfy the demands of spatial analysis. Therefore, applying the basic data of geologic survey and computer techniques to realize 3D modeling and visual analysis of engineering geology is the long-term aim we have been pursuing for.The idea of establishing 3D visual system of engineering geological information (VisualGeo) is put forward in this thesis. Firstly, according to user requirements analysis, the overall design, functional design and interface design of the system are carried out. Secondly, the 3D geological visual model based on NURBS technique is reconstructed. Thirdly, some visual functions are provided, such as display of 3D geological section map, automatic generation of contour line. And the multi-form output of the section map can be gotten. Finally, visual management and information query are achieved.Summarily, the main contents and achievements of this thesis are embodied as following:(1) To meet the particularity of geologic body and the need of actual engineering, the NURBS technique, which has been ripen in engineering and computer technology, is introduced. Through the NURBS technique, the topographic TIN model with large memory space is simplified so that the topographic outline model can be gotten, which offers prerequisite condition for the realization of 3D geological model.(2) The 2D geologic profiles are plotted using professional CAD software by means of interactive geology deciphers and the data is exchanged from the CAD software to the system. And thus the geological structure surfaces can be constructed using the NURBS technique.(3) Through body Boolean operations, the geological structure surfaces are transformed into corresponding constructional bodies. Then after rendering various textures and performing model check, we can establish 3D visual geological model which is approximately close to the realities.(4) Based on the 3D geological model, a variety of function blocks are designed to be used to analyze the visual 3D geology for geologists and designers. (5) The 3D visual system of engineering geological information for Jinping First-level Hydropower Station (JP-VisualGeo) is set up successfully. In this way, not only the idea and method in this thesis are testified practically but also the engineering geological information can be utilized roundly and dynamically. With the alteration of design options, the digitized results can be submitted in time, which leads to the significant improvement for the engineering design level. The perspective of its application would be very bright.