| There are more than 80,000 existing reservoirs in China, of which more than half are dilapidated reservoirs. Once the dam-break of these dilapidated reservoirs occurs and it will have caused huge losses of life and property of the people in the downstream area. In view of the safety problems of dilapidated reservoirs, in addition to take engineering measures such as danger-eliminating and reinforcing, research of dam-break flood evolution process and visual expression method,and analysis and assessment of the influence on the downstream is also one of the important non-engineering measures of disaster prevention and mitigation.With the development of computer technology, numerical simulation method has become the main approach to the study of the dam-break flood evolution process. Based on the numerical simulation methods, a batch of software of dam-break flood simulation appeared in the world, the software can get the specified location, flood peak flow process information such as the time by specifying parameters of dam breach, but the expression, interpretation and analysis for the results of numerical simulation are too simple. GIS with the advantage of storage, management, expression, analysis for geographical spatio-temporal data can play a huge role in the application of dam-break flood process simulation, but the existing methods of GIS such as non-source flood and source flood ignore the physics and dynamics factors in the process of flood routing, the timeliness and reliability of simulation results are poor. Aiming at this problem, this paper introduced SPH method into GIS for the application of dam-break flood process simulation, and regards the massive simulation data caused by SPH method as a new dynamic data source of GIS. Study on the key technologies of 3D dynamic visualization of dam-break flood process such as spatio-temporal modeling, visualization, analysis and so on. The main research results are as follows:(1) Designed a dam-break flood process dynamic visualization technology solutions. First construct fluid surface grid based on the fluid particle data; Then model the fluid surface grid data and other geographical data base on 3D spatio-temporal data model, get a 3D spatio-temporal database; Finally realize the dam-break flood process of time and space of 3D visualization and analysis by 3D rendering engine and visualization technology.(2) Put forward a 3D spatio-temporal data model of Dam-break flood process, designed the flow of spatio-temporal modeling of the multi-source data in dam-break flood spatial and temporal process. Based on the characteristics of spatio-temporal data in dam-break flood process simulation and dynamic visual requirements, paper put forward a 3D spatio-temporal data model, which abstract the spatio-temporal data for geographic entities base on the thought of object-oriented, and managed geographic entities by classification and layer thought. Based on the data model, the paper designed the process of spatio-temporal modeling of the multi-source data.(3) Designed and implemented several kinds of spatio-temporal data visualization expression analysis methods. Analyzed and summarized the main characteristics and target of spatio-temporal data dynamic visualization, elaborate the basic idea of space-time filtering, and gived the concrete implementation method; Based on space-time filtering mechanism, the paper designed and implemented several kinds of spatio-temporal data visualization expression analysis method.(4) Developed and completed the dam-break flood process simulation of 3D visualization system. The system consists of 3D model editing subsystem, scene organization subsystem, visual subsystem and several basic functional modules. System provides a preliminary, integrated technology solution for dam-break flood process visualization expression based on SPH method. |
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