Numerical analysis using a newly developed 3D finite element procedure - Part II: Stress behavior for local loading

A number of artificial islands have been created in Osaka. These reclaimed islands have undergone much difficulty in the ground behavior due to unforeseen occurrence. These problems are caused by the following special features of the seabed in Osaka Bay. The modeling of permeability of the Pleistocene sand layer is not easy. And the Pleistocene clays deposited are socalled "quasi-overconsolidated clays". Most of all, one and two dimensional approaches have a limitation in assessing the stress and deformation due to reclamation. Because the seabed was observed non-homogeneity and irregular thickness. For the above mentioned reasons, the Author developed 3D FEM program using the elasto-viscoplastic constitutive model. And this developed 3D program has been validated and demonstrated by comparison with existing 2D studies. In this paper, stress and deformation analyses of the Pleistocene foundations for group pile supported elevated bridges were conducted with the developed 3D elastoviscoplastic finite element code. The calculated performance showed a serious reduction in stress increment with depth, even at the center of the group piles. As far as the deformation is concerned, a compressive deformation naturally took place associated with the lateral expansion caused by the loading at the group pile.