The back analysis of pressuremeter test of sand is discussed. The measured data of pressuremeter test are used for inversive determination of the in situ state of the soil instead of the material parameters. The material parameters can be determined from the conventional laboratory tests. The characteristics of new hypoplastic model which is independent of soil state are used. The main contents include: establishment of the numerical model based on the finite element method for the back analysis

and determination of the material parameters for a specific sand using the related data from the literature; verification of the numerical model by simulating laboratory pressuremeter test; further numerical study carried out by changing the initial stress and relative density of soil

and establishment of relation between the measured pressuremeter

the stress and the relative density of sand based on the numerical results

which can be used for the back analysis.