Abstract: Soil parameters are key to the reliability of numerical analysis in geotechnical engineering. Various parameters stand in different ranges and are often related to each other. This paper discusses the main indexes of soil physical properties, soil strength parameters; and their empirical ranges, and presents a relationship of Poisson’s ratio versus pressure coefficient of earth at rest. It also summarizes typical empirical approaches for determining soil deformation modulus and the ranges of Duncan-Chang model’s main parameters. Focusing on the major problems in numerical calculation, The author suggests possible causes, solutions and precautions to help choose parameters in geotechnical test and numerical analysis.

Key words: soil mechanics, index of physical property, Duncan-Chang model, coefficient of earth pressure at rest, finite element method