Abstract
Back analysis of a ground deformational behavior involving nonlinear behavior is discussed. It is of primary importance to make reliable prediction of deformational behavior for shallow tunnels in soft ground. However, predictions made often prove to be incorrect due to complexity of constitutive law and other relevant factors. Back analysis therefore becomes more important, for it may be used to interpret measured displacement to derive non-linear material characteristics. The paper shows some example in which a deformational mechanism is studied in the light of inhomogeneous distribution of Young's module, from which a logic is derived to identify two different types of non-linear constitutive relationships.
