Abstract: Fast, efficient and accurate 3D geological model construction is the key to expand the application of 3D geological model in engineering. There have been many methods proposed to build a boundary representation 3D geological model quickly and automatically. However, present methods cannot accurately identify the interlayers and lenses, which leads to an error of mesh illegal intersection on the side boundary of the model. To solve this problem, a method of side boundary reconstruction that building the model overall firstly and making partial adjustments secondly to avoid illegal mesh intersection on the side boundary of the model is proposed based on the rapid mesh intersection algorithm of the geological model with 4 steps. Firstly, construct the upper and lower surface model of each stratum based on the boreholes data. Secondly, build the side boundary surface based on the stratum sequence. Thirdly, classify the stratum blocks into ordinary stratum and interlayer, and obtain the intersection polygons of the triangle mesh on the side boundary of the interlayer and its intersected meshes on the ordinary stratum through the mesh intersection algorithm. Finally, realize the reconstruction of the side boundary of the model with triangulating the intersection polygons and updating to the mesh list of strata. Apply this method to the modeling on a certain area, and the results show that the method is capable of quick and highly automatic reconstruction of the side boundary with the existence of interlayers and lenses.

Key words: 3D geological modeling, model updating, boundary reconstruction, automatic modeling