Abstract: Coupling and systematic development methods of three dimensional geographic information system (3DGIS) and finite element method (FEM) have recently become the research hotspot in interdiscipline of geotechnical engineering and GIS. By explorating and programming of open source libraries such as MeshPy, GRASS GIS, vtkPython and Scipy, and using Python as "glue", the platform framework of seamless coupling between GIS and 3D FEM was eventually built. Under the constraint condition of geometry, Delaunay properties, angle, area and volume, MeshPy's Triangle and TetGen library were used to generate the triangle and tetrahedron grids for finite element numerical calculation and the insert algorithm of constrained Delaunay triangulation (CDT) and the grid quality control method were expounded. Combining with related module and algorithm provided by vtkPython, the surface model of a coal mine dump was established and a new interpolation method considering both lineament and triangle barycenter coordinate was put forward, which can effectively eliminate the elevation distortions in certain areas. The program including Duncan-Chang E-μ model and nonlinear solution algorithm based on mid-point incremental method was developed and was verified by the numerical simulation of indoor large-scale triaxial shear test. Finally, taking Zhundong coal mine as an example, the 3D finite element numerical calculation about the heaping process of the northern dump was carried out. Combined with the spatial distribution of material height and thickness in GRASS GIS, a preliminary research on the displacement variation of dump slope was accomplished. It is shown that the vertical displacement is mainly controlled by material height and thickness. The maximum horizontal displacement mainly appears in slope edges of each step, which is consistent with the actual situation.

Key words: three dimensional geographic information system (3DGIS), open source software, finite element method (FEM), seamless coupling, dump slope