Research For Mesh Generation Of Finite Element Methods For Underground Cavity Group

Based on studying numerous algorithms of automatic mesh generation and concluding their advantages and disadvantages, combined advancing front algorithm, paving algorithm, plastering algorithm and other mesh generation techniques, this dissertation puts forwards a new automatic mesh generation approach, which is an efficient, accurate and simple algorithm for generation of quadrilateral or hexahedral finite element meshes.In 2D FEM quadrilateral mesh generation, the complication of underground caverns has been well considered. All caverns are drawn in AutoCAD and defined as an initial front boundary, then nodes and elements are newly generated by angle division. This method well controls both mesh density and quality.Aiming at complicated underground caverns, such as surge chamber and underground bifurcation, this dissertation puts forwards hexahedral mesh generation, which firstly establishes model and forms initial quadrilateral mesh, gets direction and generation density, then hexahedral elements are newly generated.Resting on kinds of methods of data interface between AutoCAD and advanced computer languages, this paper selects Visual Fortran6.0 programming for DXF document. The subdivision meshes are modified and adjusted after displayed and observed in CAD. This method can quickly and accurately realized combination between AutoCAD and FEM computer program.The stability of surrounding rock analysis on the underground caverns has been done in the end of this dissertation.