According to the complex geological phenomena in rock and soil medium and the features of strata
a three dimensional strata model is established. The function of 3-dimensional strata information system(3DSIS) in geotechnical engineering is to make these phenomena visualized
to process the data collected from one project using database and analysis. The function and application of 3DSIS are shown. The integrated model of 3DSIS
numerical analysis method and expert system is suggested.