A thesis study submitted in partial fulfillment of the requirements for the degree of Masters of Engineering, School of Civil Engineering

Thesis (M.Eng.) - Asian Institute of Technology

In this study, a model which could well rep resent the shield behavior in clayey ground was developed. In modelling the loads acting on the shield, it was considered as a large load cell. More attention was paid to model the force on cutter face and that on skin plate. Force due to the earth pressure on the skin plate is obtained considering the relative displacement of ground around the skin plate. At the cutter face, earth pressure acting on the circumference and pressure on cutter face from the mud in the chamber were also considered in addition to the earth pressure normal to the cutter face. This model was used to estimate the clayey ground properties by reverse analysis method. Ground properties were obtained by applying non- linear least square method to the equilibrium conditions of forces and moments . Modified Marquart method was used for reverse analysis and linear and non- linear parameters were separated in the reverse analysis. The overall scheme of reverse analysis was implemented in a computer program which was coded in FORTRAN 77. Validity of the model was studied comparing the ground properties obtained from the reverse analysis with some of the available values. Data used in the reverse analysis was obtained from the single track railway tunnel project, which was constructed at the seaside of Tokyo bay by mud shield driven method. Therefore, ground properties obtained from this study can be used in Tokyo clay layer.