在三维地质体模型构建过程中所采用的数据多为钻孔数据,而研究区域内原始钻孔数据通常数量有限且分布不均,难以构建出既能够准确地反映研究区域地质构造,又具有良好可视化效果的三维地质体模型。针对此问题,本文对虚拟钻孔概念进行延伸,提出了用于三维地质体建模不同阶段的三种虚拟钻孔概念,并基于此设计了一种虚拟钻孔控制的三维地质体模型构建方法。首先,根据原始钻孔数据空间分布特征,自适应地确定插值点位,并采用克里金插值算法构建插值加密虚拟钻孔;其次,根据尖灭规则构建尖灭处理虚拟钻孔,采用改进的自适应蝴蝶细分算法构建细分光滑虚拟钻孔;最后,利用原始钻孔、插值加密虚拟钻孔、尖灭处理虚拟钻孔,以及细分光滑虚拟钻孔构建研究区域内符合地统计学规律且具有C¹几何连续性,可视化效果良好的三维地质体模型。与将虚拟钻孔作为专家知识补充手段的传统建模方法不同,该建模方法将虚拟钻孔引入三维地质体构建的各个环节中作为核心的算法中间单元,有效简化了建模算法的实现过程,确保了算法的稳定性与高效性。

Construction of 3D geological models is a very efficient way to create a good understanding of geological features. It is a comprehensive method to geologists, geophysics engineers and GIS experts who sometimes need to visualize an area to accomplish their researches. Geological drill hole records have been widely used as the main data sources in 3D geological model construction approaches. However, since the original drill hole sampling points are limited and maldistributed, it is difficult to construct 3D geological models that not only show favorable visual effect but also reflect accurately the geological structure of surveying regions. To solve this problem, this paper proposes a 3D geological model construction approach based on virtual boreholes. Firstly, according to the spatial distribution of original drill holes, positions of interpolated points are determined self-adaptively and Kriging interpolation algorithm is applied to the construction of interpolated virtual boreholes. Secondly, according to the pinch-out rules, the pinch-out virtual boreholes are constructed, and the improved self-adaptive butterfly subdivision algorithm is applied to the construction of subdivided smooth virtual boreholes. Finally, with the original drill holes, the interpolated virtual boreholes, the pinch-out virtual boreholes and the subdivided smooth virtual boreholes, 3D geological models of survey regions can be constructed, matching geostatistics patterns, being C¹ geometric continued, and showing favorable visual effect. Differing from the traditional modeling methods that regard virtual boreholes as complements to expert knowledge, the proposed method introduces virtual boreholes into each step of the construction of three-dimensional geologic models as the intermediate elements of the core algorithm, simplifying the realization process of the modeling algorithm effectively, and ensuring the stability and efficiency of the algorithm.