Geological Engineering in complex geological bodies of various geological information can be seen as a function of three-dimensional space, using field measurement data respectively to establish appropriate surface fitting function, and use of computers to create a three dimensional geologic model, achieve the Visual expression of geological information in engineering rock mass distribution, increase awareness, guidance for geological rule of geological surveying and construction of projects and monitoring purposes. This article provides an analysis of three dimensional modeling and visualization of complex geological key technical problems and preliminary application in xiangjiaba dam area of three dimensional geologic modeling.
First, the preamble
Geological Engineering in complex geological bodies of various geological information can be gained through field exploration or monitoring devices record measured, but are generally scattered data, engineering workers in its engineering rock mass difficult to has a comprehensive and intuitive grasp of the distribution. Various geological information, including surface terrain, and groundwater bit, and formation interface, and fault, and section acting, and weathered with distribution, and intrusion body and the various Earth physical, and geochemical, and rock soil body of physical mechanical parameter or data of equivalent surface (line),, are can seen as is three dimensional space in the of function, using various field measured information respectively established corresponding of surface intends hop function, turn using computer established three dimensional geological model, reached intuitive to expression geological information in engineering rock soil body in the of distribution law, and improve for geological law of awareness, and guidance geological project of survey construction and the monitoring of purpose. Establishment of three dimensional model of geological engineering of complex geologic body, rock interface combined with a discontinuity, lifelike picture reflected the subsurface geological structure, for geological engineering workers analysis of engineering geology and rock-soil mass structures found law provides a new set of research methods and research methods.
Second, the complex geology of three dimensional modeling and visualization, and software development
Present situation of domestic research and development: TITAN three-dimensional modeling software was developed by Beijing Oriental technology Titan TITAN geo-a component of the integrated information system is based on modeling the ideological development of the framework, using parallel or parallel profile data to build arbitrarily complex three dimensional space of true three dimensional solid model of the shape object. TITAN three dimensional built die software of part has: (1) profile data processing module, established profile data, for established three dimensional entity model provides by series parallel of profile composition of framework data, data profile by polygon, and ring and point element composition; (2) corresponds relationship processing module, established profile Zhijian, and polygon Zhijian, and ring Zhijian and point Zhijian of corresponds relationship, for established three dimensional entity model provides profile between of one by one corresponds relationship, thus established built die element Zhijian in three dimensional space in the of contact; (3) model processing module, established entity model, with profile data and profile between of corresponds relationship established up three dimensional entity model, and can on model for arbitrary cutting, and calculation area and volume of processing. This software is only three-dimensional modeling and graphics engine, applied widely. However, when you face the specific professional, you need to add or expand the professional module, such as engineering geology module. Panoramic view of the current situation of research and development of several software, for geological engineering modeling and analysis of complex geological bodies targeted is not strong, did not fully reflect the particularities of geological engineering, geological engineering production and not be very good to meet actual needs of the research
Three complex geology, geological engineering modeling and visualization of three dimensional analysis of key technology issues
(A) discrete interpolation and data fitting
Geological information of the fitting and interpolation functions according to the actual survey data, measured data is more accurate, be more authentically depicting the geological model of the spatial distribution of the information. For the different geological information, use different fitting function. Surface topography measurement data (x, y coordinates and surface elevation z), buried depth of groundwater level measurements of surface generated graphics can be summed up in two-argument fitting and interpolation of the discrete data. Surface interpolation function has the following structure method, and is inversely proportional to the distance-weighted method, method of radial basis function interpolation, plane elasticity theory method of interpolation, which also applies to a single interface, geophysical data, continuous formation of rock and soil geochemical exploration data and spatial distribution of physical and mechanical parameters of rock mass.
(B) three dimensional data structures
Geological Engineering geologic body is generally irregular shape, curves and surfaces in computer graphics is always separately by many tiny line segments and small triangular surface approximation, to simulate the boundary of the lithology and rock surfaces, that interface and rock surface rock formation are the collections of many tiny line segments and small triangular surfaces. This requires that you must have a valid hierarchy of three dimensional data structures, such as geology and engineering geology in the space of points represented by the three-coordinate component of that tiny line segment is composed of its two endpoints, geological boundaries is made up of tiny line segments all part of the boundary, and rock surfaces made up of tiny triangular surface. Three-dimensional data structures to ensure effective realization of human-computer interaction and query.
(C) analysis of the surfaces and topology of three-dimensional intersection
Geological body in the exists large various level, including surface, and groundwater bit surface, and formation level,, dang appears formation not integration, and formation tip fight and groundwater out dew Yu Valley surface, scenario Shi, on natural will encountered surface between seeking cross of problem; geological body three dimensional model of upper boundary is surface surface, through mathematics method intends hop out of rock level or underground water level surface not should beyond surface surface, is beyond part not should display. Similarly, when you show when several strata, per stratum should be below a rock on its boundary. The other hand, when in profile graphs, geological boundaries of drawing was through the display profile and interface of various geological derived line of intersection. Intersect the surface intersection between geo-interface, and intersect two categories of geological profile and interface issues. From the perspective of geology, topology is the relationship between geologic objects form storage layer overlying the topology table, underlying and cross-cutting, such as stratigraphy and geological spatial relationships. Using visualization techniques can construct from a huge geological survey data for edges broken geological engineering stability and deformation of underground Chamber, played a key role in rock formations and structures, and displays the trend of its scope, and meet each other, help engineering personnel to correctly interpret the original data and provide decision support for geologic analysis of specific issues.
Four, three dimensional modeling of complicated geological entity and preliminary development and application of visualization technology
(A) geological engineering complex three dimensional modeling and visualization of geologic body
Based on discrete sampling data of plug value and intends hop of thought, is discrete data transformation for continuous curve surface, geological engineering, complex geological body three dimensional built die and Visual of of process is, from exploration database in the extraction various geological information of coordinates location and the rock soil body of physical mechanical parameter, through different of intends hop and plug value function get geological level (surface) and geological entity of three dimensional computer graphics display, expression geological information in research regional within of distribution law. After building the geological rock layers and geologic entity, from any angle to establish model and realization based on the specified section to, generate vertical inclination and angle sections.
(B) development and application of preliminary
Engineering survey and spatial databases to collect survey data into the data table, these data tables include not only the location of geological information data, attribute data is more important to provide. Lithology data tables, for example, requires entry hole termination depth of number, the starting depth, rock strata, layer thickness, lithology, stratigraphy code, rock to rocks, rock orientation, inclination, contact relationships, geological description and other data. With the development of engineering survey, can easily be modified to add and manage survey data. Xiangjiaba dam site engineering survey data, the establishment of a three dimensional geologic map at the right bank. To home dam a dam area bottom formation rock sexual combination for: fourth Department collapse breaking stacked property, Jurassic mudstone, and powder sand mass mudstone, and mud mass powder sandstone, three stack Department Shang Commission thick to giant thick layer shaped fine to in the grain sandstone, three stack Department Shang Commission thin to in the thick layer shaped powder sand rock, and powder sandstone, three stack Department Shang Commission in the thick to thick layer shaped in the rough sandstone. Stereogram drawn by limited engineering survey data, to better meet the precision of engineering geology.
Geological Engineering of complex geologic body modeling and visualization study of rock-soil mass structure in geological engineering, intuitive expression of geological information in geological engineering in rock-soil mass distribution laws and guidance of geological surveying and construction of the project is of great significance. Geology is a complex of engineering rock mass of irregular shape, there is a variety of geological rock layers and structure, full expression and rock formations and geological information structure, cutting each other, and combination relationship between location, geological engineering of complex geologic body modeling and visualization of three dimensional research is promising.
 Sun Guangzhong, engineering geology and geological engineering, s Sun Guangzhong, Seismologic press, June 1993
 such as Huang Dingcheng, Henan science and technology of the Chinese Earth science toward 21st century press, October 1995
 Zhang Mingding, of the systematic thinking of hydrogeology and engineering geology of the Northwestern Polytechnical University Press