面向GTP的三维地质模型空间剖切方法与应用

Research on Cutting Method for 3D Geological Model Based on GTP

广义三棱柱(GTP)是近年来提出并被广泛应用于三维地质建模领域的一种较为成熟的空间数据模型,可满足大多数地质钻孔数据的三维地质建模的要求。然而,现有针对GTP模型的三维空间剖切分析方法,仍无法适用于偏斜钻孔数据所建三维地质模型高效多次任意剖切、不能支持较为复杂的地质模型空间分析的问题。本文通过对GTP剖切算法改进研究,提出了采用动态四面体剖分法减小数据冗余;鉴于GTP形态较为复杂,可对剖切后保留多面体进行拓扑关系的重组,解决任意多次剖切问题;将多次"面-体"形式的单剖切运算组合为一次"体-体"形式的复合剖切运算的方法,可高效实现对三维地质模型空间分析。本文着重面向GTP体元的多重任意切剖平面的剖切问题,在分析了GTP体元特征的基础上,弥补了三维地质建模领域中对GTP体元任意、多重剖切方法研究的不足。应用实例表明,上述改进算法可以提高GTP剖切计算速度,并能够快速实现巷道掘进模拟,以及空间开挖模拟等复杂的空间分析功能。

Generalized three prism （GTP） is an important 3D spatial data model which is widely used for geological modeling. In recent years, with the development of computer visualization technology, GTP geological model construction method based on drilling data is maturing. However, the research on the 3-D profile cutting algorithm of GTP spatial data model still focuses on the single plane cutting section, and lacks mature algorithms to support the multiple efficient arbitrary plane section of single GTP model. Research on multiple cutting method of GTP model is one of the most important requirements of the 3D geological model applications in practice; at the same time, multiple GTP cutting algorithm can also provide efficient technical support for the spatial opera- tions of GTP model and 3D geometric entities. The current generalized three prism （GTP） cutting algorithms are not suitable for dealing deviate borehole data with dimension reduction method or tetrahedral mesh generating method, and would lead to excessive data redundancy and low algorithm efficiency. In addition, it is unable to realize multiple arbitrary cutting operations, and could not support the more complicated spatial analyses of geological model. This article proposed an improved dynamic tetrahedral mesh generating method to reduce the data re- dundancy by restructuring the retained polyhedron, which is constructed after cutting operation, based on topological spatial relations. The multiple arbitrary cutting problems were solved and several ＂plane-body＂ single cutting operations were combined into a single ＂body-body＂ composite cutting operations to realize the 3D geological model space analyses. This paper focused on multiple arbitrary cutting plane section problems of the GTP body based on the analysis of the GTP body element characteristics, proposed a solution which aims to make up the deficiencies of the research on the arbitrary and in multiple cutting plane section of GTP body element in the field of three-dimensional geological modeling. Application examples show that： the above three points could improved GTP cutting operation speed and are able to realize complicated spatial analyses such as space excavation and tunneling simulation more efficiently.