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

Thesis (M.Eng.) - Asian Institute of Technology, 1999

This study presents the consideration on the physical meaning of the parameters associated with unsaturated-saturated seepage analysis. Recently, unsaturated-saturated seepage analysis method formulated by Finite Element Method (FEM) has been applied for various type of actual projects such as tunnel construction in urban area, in order to investigate the influence of ground water behavior to surrounding environment. In general, the accuracy of analysis is heavily dependent on how to evaluate input parameters involved in the governing equation. Since the governing equation of unsaturated-saturated seepage analysis is a nonlinear differential form, the problem mentioned above is especially serious. From literature survey, it is pointed out that the discussion how the parameters in an unsaturated region are associated with those in a saturated region has not been made sufficiently. Therefore, this study aims to make the physical meaning of parameters involved in unsaturated-saturated seepage analysis theory obvious, and propose the methodology to evaluate input parameters reasonably. Especially, the relative continuity of parameters between a saturated region and an unsaturated region is focused on. To cope with the problem related to the relative continuity of parameters, the adoption of modified factor is proposed. Through case studies by using FEM code, the effectiveness of modified factor proposed in this study is investigated and concluded that The methodology proposed in this study makes the convergence of iterative calculation procedure faster. Essential, it means timesaving of computational time.