INVERSE ANALYSIS OF SOFT GROUNDS CONSIDERING NONLINEARITY AND ANISOTROPY

摘要

The inverse analysis method, used to accurately predict the two-dimensional deformation behavior of soft grounds, is discussed in this study. To ensure safety when constructing on a soft ground, in-situ observations are usually made. An inverse analysis is then effective for identifying the in-situ parameters of the ground and for predicting future deformation based on the parameters. The settlement, the lateral displacement, and the pore water pressure are measured during the construction of the structure. It is generally difficult to predict the lateral displacement. In this research, therefore, the cross anisotropy (transverse isotropy) of the ground is introduced to overcome the difficulty of predicting the lateral displacement. Furthermore, a simplified hyperbolic model is introduced to simulate the nonlinear shear behavior. The model is convenient for use with the inverse analysis, since it does not require many parameters. The measured pore water pressure is seldom used in the inverse analysis, because information on the pore water pressure is not required, from a mathematical standpoint, in order to identify the consolidation parameters. The effectiveness of applying the measured pore water pressure for the prediction of future consolidation behavior, is clarified in this study. As a result, the hyperbolic nonlinear model and the assumed anisotropy were found to be useful in predicting the future deformation behavior of clay. Furthermore, the pore water pressure measurement was proved to be effective for the predictions in this study.