Formulas of infinite element with 6 nodes are presented; and an object-oriented geotechnical infinite element(IE)-finite element(FE) coupling software based on Windows is designed by combining VC++ with Matlab. As its application
the stability of underground excavation of a hydropower project in Yunnan Province is calculated by FEM and IE coupled with FE method; so that the accuracy of formulas is proved. The analysis of the example shows that
when infinite or semi-infinite calculating zone is involved in
the application of IE coupled with FE may eliminate “boundary effects” and raise the efficiency of calculation.