Abstract
The pore pressure coefficient B, which is measured on triaxial test, is useful for evaluating degree of saturation of specimen. However, the influential factors on this B value other than degree of saturation have not been investigated in detail up to now. In this study, first, Henry's law that indicates dissolved air in pore water was applied to the existing constitutive model for unsaturated soil in order to express the behavior of pore air on unsaturated soil extremely close to fully saturated state. Next, the influential factors, such as degree of saturation, confining stress and back pressure, were investigated through numerical simulations with using newly obtained model. Consequently, it was found out that B value depends on not only degree of saturation but also stress state.