A preliminary study on the relationship between survey parametersand constitutive model parameters

For the numerical simulation analysis of underground engineering including underground excavation and mine shaft, the reliability of the results depends on two key factors, one is the constitutive model used to simulate the surrounding rock and soil, the other one is the reliability of these constitutive model parameters.Conventional geotechnical survey can’t provide parameters for advanced geotechnical constitutive model (such as modified Cambridge model, small strain model, etc.), analysts generally determine the value of the parameters according to experience, which brings great uncertainty and randomness to the analysis results.It is more accurate to determine the parameters of the constitutive model of rock and soil by the inversion of the measured displacement response, but the determined parameters of rock and soil are usually only applicable to a single target geological situation, and can not be extended to other projects.In this paper, based on the intrinsic relationship between the constitutive parameters of rock and soil and the physical indexes of conventional investigation and the results of mechanical tests, as well as the regional characteristics of the parameters of rock and soil, a certain number of open excavation foundation pit projects in Beijing area are taken as analysis samples.Based on the determination of the parameters of the constitutive model of rock and soil by inversion, this paper further investigates the relationship between the parameters of the constitutive model of rock and soil and the physical indexes of conventional investigation and the results of mechanical tests, and tries to find out whether there is a strong correlation between them and to establish the relevant formulas.The results of the study hope to determine the parameters of the advanced rock and soil constitutive model from the surface level for the design of the foundation pit or shaft support by the general survey physical index and the basic mechanical test results, and to provide the basic data and methods of preliminary exploration.