Abstract:
According to the geologic investigation data of line 1 and line 2 in Ningbo rail transit, the probability distribution of physical parameters for the typical soils in Ningbo area were studied. Empirical equations between the basic physical indexes including the natural density (ρ) and the natural water content (w) and other physical indexes including the void ratio (e) and the liquid index (IL) and the plasticity index (IP) were established by means of a regression analysis method. It is found that the physical index probabilities of every typical layer in Ningbo area show a good normal distribution. Furthermore, the physical parameters including ρ and w and e and IP have little variation and can be considered as a constant in the practical reliability design. However, the variation of liquid index is large and should be considered as a random variable in the geotechnical reliability design in Ningbo area. Moreover, the physical parameters including a void ratio and a liquid index are in a good positive linear correlativity with the natural water content. Meanwhile, the void ratio is in a good negative linear correlativity with the natural density. However, the plasticity index is in a poor correlativity with the natural density and water content, and the liquid index is also independent on the natural density. Study results could be used as the basis of physical parameters selection in the soil and foundation reliability design in Ningbo area.