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由于地质体存在断层、尖灭、出露等复杂地质现象,在三维地层建模时,为了表达这些现象,无论是面模型还是体模型或混合模型,都存在空间分割或曲面求交线的问题。由于地质体拓扑关系的复杂性、数据误差以及计算机精度问题,使得这些模型在实际建模过程中常常失效。运用水平集理论可以有效解决这一问题,水平集用隐函数表达曲面(或超曲面),可以实现复杂地质体的表达及并、交、差等拓扑运算。在三维地层建模中,插值生成各种地质界面后,用水平集表达这些地质界面,利用水平理论完成各种复杂的拓扑操作,建立以水平集表达的三维地层模型。在此基础上,插入水平集表达的各种工程活动界面,利用水平集理论进行拓扑操作,可构建各种工程活动后的地层模型。再利用Marching cube算法抽取各种地质界面或工程活动界面,构建可用于实时可视化或用于工程评估(如有限元计算)等的NMTINF-BR地层模型或工程活动后的NMTINF-BR地层模型。
Due to the existence of faults, pinch out, and other complicated geologic phenomena, in the modeling of 3D stratum, in order to express these phenomena, both the surface model and the body model or the mixed model have the problem of spatial division or surface intersection . Due to the complexity of topological relations of geologic bodies, data errors and computer accuracy problems, these models often fail in the actual modeling process. The level set theory can effectively solve this problem. The level set can express surface (or hypersurface) with implicit function, which can realize the expression of complex geological body and the topological operation of intersection, difference and so on. In the modeling of 3D stratigraphy, after generating various geological interfaces by interpolation, these geological interfaces are expressed by horizontal sets, and various topological operations are completed by using horizontal theory, and a 3D formation model expressed by level sets is established. Based on this, we insert various engineering activity interfaces expressed by level sets and use topological theory to make topological operations, then we can construct various formation models after engineering activities. The Marching cube algorithm is used to extract various geological interfaces or engineering activity interfaces to construct the NMTINF-BR stratigraphic model or engineering NMTINF-BR stratigraphic model that can be used for real-time visualization or for engineering assessment (such as finite element calculation).