Abstract: The 3D geological modeling for super long tunnel site faces problems such as large human-computer interaction, long time-consumption, and deviation of modeling results from expectations. To deal with these problems, the authors proposed a set of efficient modeling schemes that conform to the geological characteristics of the tunnel site based on some super long tunnel projects in southwest China. According to factors such as the types of lithology and the geometric features of the geological surface, the processing method and naming rules for the initial modeling data were formulated, and the mapping system of “data name-geological surface modeling scheme” was established. Besides, the corresponding modeling schemes of different types of geological surface and the intersection relationship between geological surfaces were clarified, and based on discrete smooth interpolation and multi-condition constraint method, the rapid and accurate modeling scheme of geological structure model was realized. Taking Daliangshan No.1 and No.2 tunnels and Siguxi tunnel under construction as examples, the proposed modeling scheme was used to construct the 3D geological model of these tunnel sites. The results show that the modeling scheme proposed in this study can realize the automatic construction of various complex geological surfaces on the premise of ensuring the precision of the model. Therefore, the modeling efficiency is greatly improved, and the geometric shape and topological characteristics of the generated geological surface also meet the expectations of the modeler.

Key words: geological model of tunnel, discrete smooth interpolation, geological modeling scheme, geological surface modeling