3D fusion modeling of multi-scale geological structures based on subdivision-NURBS surfaces and stratigraphic sequence formalization

Abstract Multi-scale 3D geological modeling technology is a vital issue to illustrate the complex geological conditions of infrastructure projects at the regional scale, engineering scale, and outcrop scale. It is also the computational basis for numerical geotechnics and seepage stabilization studies. However, empirical interactive modeling methods based on expert knowledge are mostly applied in existing numerical researches and geological structures at different scales are modeled independently, which reduces the credibility of simulation. Therefore, this research states a 3D fusion modeling method of multi-scale geological structures: (1) The multi-constraint NURBS modeling method for multi-valued strata at regional scale and the discrete fracture network modeling method for discontinuities at outcrop scale are presented. (2) The subdivision-NURBS modeling method for multiple genera geological bodies at engineering scale is raised so that the genus characteristics of geological bodies can be expressed in an objective parameterized way rather than in an empirical interactive-modeling way. (3) The Enhanced Boolean Logic Sequences of Oriented Geological Interfaces (E-BLSOGI), where the multiple genera geological bodies at engineering scale and the discontinuities at outcrop scale are additionally introduced based on the BLSOGI method offered in authors’ previous study [1], is provided to achieve 3D fusion modeling of multi-scale geological structures. The practice indicates that the 3D fusion modeling of multi-scale geological structures is realized, evidencing that results without integrating multi-scale geological structures underestimate the compressive stress (16.37, 10.52, and 33.09%), tensile stress (16.57, 21.57, and 10.76%), and displacement (7.17, 47.62, and 33.62%) of the dam foundation in x -, y -, and z-, directions, respectively.