BACK ANALYSIS TO MODEL OUT ROCK MASS BEHAVIOUR DUE TO INHOMOGENEITY AND ITS APPLICATION TO CAVERN CONSTRUCTION

Abstract

This paper proposes an innovative back analysis method to model out inhomogeneous behaviors, which is suitable for cavern excavation in rock masses with a loosened or fractured zone. This method allows us to estimate the extent and characteristics of inhomogeneous zones with iterations, defining the reduction factor of elastic modules by strain outputs and following the back analysis formulation to take initial stress parameters as well as non elastic strains as unknowns with minimum norm solution. It is applied to the numerical experiments and also the actual cavern construction problem and the results suggest that more reasonable strain distributions with proper reduction factors can be appropriately estimated in a reasonable calculation time.