NorNickel’s Polar Division, Norilsk, Russia:

T. P. Darbinyan, Director of Mining Practice Department, Candidate of Engineering Sciences
T. S. Mushtekenov, Deputy Director for Mineral Resources

Geotechnical Engineering Laboratory, Gipronickel Institute, Saint-Petersburg, Russia:
A. E. Rumyantsev, Chief Specialist, Candidate of Engineering Sciences, rumyantsevae@nornik.ru
Yu. Yu. Golovchenko, Junior Researcher

Continuously rising standards of the FEM-based stress–strain modeling of complex geological structures implacably overlaborate a model framework geometry. Different defects may arise as a consequence, such as holes in polygonal meshes, intersections of planes, degenerated polygons, or triangular polygons with one angle greatly exceeding the other two angles. This complicates operation, disables generation of a quality mesh of finite elements and sometimes makes the use of the initial geometry impossible. This article offers algorithms to remove defective sites from the skeletons of geological structures in numerical modeling. Furthermore, the method to optimize topology of initial skeletons is described; this method uses an outside software (Autodesk 3ds Max) and ensures a maximally beneficial ratio of the polygonal mesh topology quality and the initial geometry preservation. This algorithm helps eliminate local crowding points in the finite element mesh and possible stress raisers which take no considerable part in geometrical amplification. This article describes the application results of the algorithms as the case-studies of skeletons of complex geological structures. The comparison of the finite element mesh quality and number of finite elements for the skeletons with and without optimization reveals the improving quality of the finite element meshes with the decreasing number of finite elements in case of the skeletons after topology optimization and removal of defects. The algorithms are especially effective in large-scale modeling when the number and quality of finite elements in each part of a model essentially influence the time and accuracy of computation.

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