Sensitivity Analysis Of Back Analysis Model Of Circular Tunnel With Transversely Isotropic Rock Mass

In the geotechnical engineering back analysis theoretical study,the displacement back analysis method in which considers the layered rock mass as a transversely isotropic rock mass,due to its high applicability and good accuracy,the parameter sensitivity of the transversely isotropic rock displacement back analysis model and stability analysis of parameter inversion have become a very important research topic.In this paper,two back analysis models under different assumptions of stress in transversely isotropic rock masses are studied.The single-factor sensitivity and multi-factor sensitivity of the analytical solution of the back analysis model to rock mechanical parameters was analyzed.Combined with the FLAC3 D numerical model,the sensitivity of the two back analysis models in the calculation of the geo-stress parameters was analyzed.The significant influencing factors and parameter accuracy of the application of the back analysis model engineering application are obtained.The results showed that the results of single-factor sensitivity analysis and multi-factor sensitivity analysis based on orthogonal test were generally consistent.The main research results are as follows: based on the analytical solutions of the back-analysis model of a circular tunnel in a transversely isotropic rock mass under biaxial stress and considering the shear stress,the single factor sensitivity analysis and multi-factor sensitivity analysis of rock mechanical parameters were carried out,the available influence range was given.Based on the basic assumptions of the back analysis modle of a circular roadway in a transversely isotropic rock mass,the FLAC3 D numerical model was established,and the influence of the basic rock mechanical parameters on the inversion of the geo-stress parameters in two back analysis models was analyzed.Through single factor sensitivity analysis and multi-factor sensitivity analysis based on orthogonal test,the sensitivity of two back analysis models to rock mechanical parameters selection in the application of geo-stress inversion was calculated.The influence trend of rock mechanics parameter values on back analysis results of geo-stress is analyzed,and the influence interval of back analysis results of geo-stress by parameter accuracy is given,which provides a theoretical reference for engineering application of two back analysis models.