A method for determining and implementing the virtual borehole based on GIS spatial analysis

In the process of 3D geological modeling, a certain amount of virtual boreholes are introduced for precisely controlling the interior and the boundary of the strata interfaces, which not only can effectively improve the mesh quality of the constructed model, but also can level up the model accuracy and its visual effects. This paper proposed a method for determining and implementing of virtual borehole based on GIS since the existed approaches for introducing the virtual borehole are mainly implemented by manual operations, which are influenced by the subjective factors and have the defects of low automatic degree, time consuming and laborious. Firstly, the borehole data and geological maps collected by various geological exploration methods are used as data sources, and two-dimensional(2D) virtual borehole points of faults formations and the modeling area are generated respectively by using the tools of ArcScan, FeatureToPoint, CreateTin, TinTriangle, CreateThiessenPolygons and Intersect under the support of ArcGIS platform; Then, the 2D points of virtual borehole points are projected into 3D points of virtual borehole by using the InterpolateShape tool by generating the strata surfaces. And then, the whole process of automatically creating virtual borehole is implemented by using the visual design tool of ModelBuilder. Finally, the acquired 3D virtual borehole are applied for the 3D geological and comparison experiments and have achieved good modeling results, which shows that the method has a certain effectiveness, practicality and operability.