层状地质体与地下工程开挖三维可视化

地质体与人造工程几何形态极其复杂，其三维可视化是地学的一个难题。通过多层DEM形成层状地质体界面，在此基础上，借助中轴变换技术概念，用地层厚度和地层中层面将地层的形状特征及拓扑关系表现出来，建立了一个判断地层任意位置属性值的方法，藉此运用空间插值技术、等值线生成技术、扫描表示技术等可视化技术将地层以及地下工程开挖绘制出来，避免了复杂的开挖体元属性及形体判断和开挖面与体元求交过程。采用此方法实现了某水电站地层与厂房基坑开挖三维可视化。

Three dimensional visualizatization for stratified geological objects and underground openings

The geometric shapes of geological objects and underground openings are very complex, so it is very difficult to visualize them. This paper describes an approach for 3-D visualization of stratified geological objects and underground openings. First, the regular grid datasets of the interfaces of stratified geological objects are formed through DEM techniques; then based on the theory of medial axis transform, the shape characteristic of strata and the topologies of strata are explicitly described with thicknesses and medial surfaces of strata and a method, by which the properties of strata in arbitrary spatial position can be obtained, is established. Based on the above notion and the application of interpolation, the extraction technique of contour lines and the sweeping technique, the implementation of 3-D visualization of strata and underground openings is achieved. This method avoids complicated estimation of the properties and shapes of opening voxels and the process of computing intersection of opening faces and voxels. As an example, 3-D visualization of strata and the foundation pit of a hydropower station are carried into effect.