Abstract: The most common gully terrain widely distributed in the Loess Plateau area of western China, this complicated landform directly affects the rock structure and stress field distribution in underground engineering, Numerical simulation has become an essential analysis tool to research this class of problems in geotechnical engineering. Against shortcomings of numerical simulation pretreatment in complex 3D Modeling and element mesh dividing caused by not visual and heavy workload, this paper presents the gully terrain 3D Modeling method based on combining HYPERMESH with FLAC3D softwar.The method build 3D Modeling and element mesh dividing by using HYPERMESH and FLAC3D software upon the geological topographic map and the stratigraphic column, an interface program is programed to create the FLAC3D calculation model.All these help to carry out the purpose of FLAC3D analysis.At last, the loess hill and gully area of northern ShanXi province is taken as a sample and the reasonable 3D numerical model is established. The results show that this method can be very valid and practicable in fast and precise modeling.

Key words: Numerical simulation, Gully terrain, 3D Modeling, Hypermesh, FLAC3D